Mammals of the Southwest Mountains and Mesas
by George Olin · English · Gutenberg #50822 · 348,567 chars · public domain (US)
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Title: Mammals of the Southwest Mountains and Mesas
Author: George Olin
Illustrator: Edward Bierly
Release date: January 1, 2016 [eBook #50822]
Most recently updated: October 22, 2024
Language: English
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*** START OF THE PROJECT GUTENBERG EBOOK MAMMALS OF THE SOUTHWEST MOUNTAINS AND MESAS ***
MAMMALS
of the southwest
MOUNTAINS
and
MESAS
by
GEORGE OLIN
illustrations by
EDWARD BIERLY
[Illustration: Uncaptioned]
Southwest Parks and Monuments Association
Box 1562, Globe, Arizona 85501
Copyright 1961 by the Southwestern Monuments Association. All rights
reserved. No part of this book may be reproduced in any form without
permission in writing from the publisher, except by a reviewer who may
quote brief passages in a review to be printed in a magazine or
newspaper.
Library of Congress Catalog Card Number: 61-11291
SBN 0-911408-32-0
Southwest Parks and Monuments Association
(formerly Southwestern Monuments Association)
First printing, 1961.
Second printing, 1971.
Third printing, 1975.
Popular series no. 9.
Printed in the United States of America
Arizona Lithographers · Tucson, Arizona
ACKNOWLEDGEMENTS
With this booklet, as with _Mammals of the Southwest Deserts_, we are
indebted to Dr. E. L. Cockrum, Assistant Professor of Zoology at the
University of Arizona who has checked the manuscript for accuracy. We
are also grateful to him for offering suggestions and criticisms which
have added materially to its interest.
The writer would also like to voice his appreciation to Ed Bierly whose
magnificent illustrations adorn these pages. His is a talent with which
it is a privilege to be associated.
Finally our thanks to the editor and his staff. It is not an easy task
to combine text with illustrations, nor to match space with type, yet it
has been done with feeling and precision.
Together, we hope that you will approve of our efforts. If through this
booklet you gain a better understanding of the mammals that share the
great outdoors with us, or if through it you should become aware of the
urgent necessity of preserving some of our wild creatures, (and wild
places), now before it is too late; we shall indeed be well repaid.
CONTENTS
Hoofed Animals 1
Bighorn (mountain sheep) 2
Pronghorn (antelope) 4
Bison (buffalo) 8
Mule deer 10
White-tailed deer 13
Elk 16
Rodents (Including Lagomorphs) 21
Snowshoe hare 22
White-tailed jackrabbit 24
Mountain cottontail 26
Pika 28
Tassel-eared squirrel (Abert’s squirrel) 31
Kaibab squirrel 34
Arizona gray squirrel 36
Spruce squirrel, Pine squirrel (Douglas squirrel, chickaree) 39
Northern flying squirrel 42
Western chipmunks 44
Golden-mantled ground squirrel 48
White-tailed prairie dog 51
Yellow-bellied marmot (woodchuck) 53
Deermouse (white-footed mouse) 57
Mountain vole 58
Western jumping mouse 59
Bushy-tailed woodrat (pack rat) 60
Muskrat 64
Beaver 67
Porcupine 72
Northern pocket gopher 75
Carnivores (Including the Insectivores and Chiropterans) 79
Mountain lion 80
Bobcat 85
Red fox 87
Gray wolf 89
Coyote 92
Wolverine 95
Marten 97
River otter 101
Mink 103
Short-tailed weasel (ermine) 105
Spotted skunk 108
Striped skunk 110
Black bear 112
Grizzly bear 117
Vagrant shrew 119
Bats 121
References 123
Index 125
[Illustration: Life Zones]
ELEVATION PRECIPITATION
FEET DRY MOIST WET
14,000 ARCTIC-ALPINE _above
ZONE[1] timber-line;
small, mat-like
plants._
13,000 _pika_
12,000 _mountain sheep_
11,000 HUDSONIAN ZONE _spruce_ _red squirrel_
10,000 _fir_ _marten_
9,000 CANADIAN ZONE _quaking aspen_ _beaver_
_Douglas fir_,
_mule deer_
8,000 TRANSITION ZONE _tassel-eared
squirrel_
7,000 _ponderosa pine_,
_mountain lion_
6,000 UPPER SONORAN
ZONE[2]
_pinyon pine_ _deer mouse_
5,000 _juniper_ _bobcat_
_sagebrush_ _pronghorn_
4,000 LOWER SONORAN
ZONE[3]
3,000 _mesquite_,
_kangaroo rat_
2,000 _giant cactus_
1,000 _kit fox_
HOT WARM COLD
TEMPERATURE
Notes
[1]THIS BOOKLET DESCRIBES MAMMALS OF THE SOUTHWEST WHICH LIVE IN THE
LIFE ZONES ABOVE THE LOW DESERT.
SEE FLOWERS OF THE SOUTHWEST MOUNTAINS FOR PLANTS OF THESE ZONES.
[2]SEE FLOWERS OF THE SOUTHWEST MESAS FOR PLANTS OF THIS ZONE.
[3]SEE MAMMALS OF THE SOUTHWEST DESERTS FOR MAMMALS OF THESE ZONES.
SEE FLOWERS OF THE SOUTHWEST DESERTS FOR PLANTS OF THIS ZONE.
INTRODUCTION
_Geographic Limitations_
The only point in the United States at which four states adjoin is where
Utah, Colorado, Arizona, and New Mexico come together. With adjacent
portions of California, Nevada, and Texas, they contain all of our
Southwestern Desert. Arizona and New Mexico especially, are known as
desert States and for the most part deserve that appellation. Scattered
over this desert country as though carelessly strewn by some giant hand
are some of the highest and most beautiful mountains in our Nation. They
may occur as isolated peaks magnificent in their loneliness, or as short
ranges that continue but a little way before sinking to the level of the
desert. On the other hand it is in Colorado that the Rocky Mountains
reach their greatest height before merging with the high country in New
Mexico, and all of the States mentioned have at least one range of major
size.
Two great highways cross this area from East to West. U.S. 66,
“Mainstreet of America,” goes by way of Albuquerque and Flagstaff to Los
Angeles; farther north U.S. 50 winds through the mountains from Pueblo
to Salt Lake City and terminates at San Francisco. Significantly, they
meet at St. Louis on their eastward course, and here for the moment we
digress from geography to history.
_Westward Ho_
St. Louis in 1800 was a brawling frontier town. Strategically located at
the point where the Missouri River meets the Mississippi, it was the
jumping off place for those hardy souls adventurous enough to forsake
the comforts of civilization for the unknown perils of the West. Already
St. Louis was one of the fur centers of the world. Fashions of the day
decreed that top hats be worn by men. The finest hats were made of
beaver fur and no self-respecting dandy could be content with less.
Trapping parties ascended the Missouri River as far as the mountains of
Montana in search of pelts with which to supply the demand. When the
animals became scarce in more accessible areas, trappers turned their
attention to the mountains of New Mexico and Colorado. Hardships of the
overland route, coupled with danger of attack by hostile Indians,
discouraged all but the most hardy of a rugged breed. These “Mountain
Men” as they became known, traveled in small parties with all the
stealth and cunning of the Indians themselves. Gaunt from weeks of
travel across the plains, they could rest in the Spanish settlement of
Santa Fe for a few days before vanishing into the mountains. On the
return trip they might again visit the Spanish pueblo or, eager for the
night life of St. Louis, strike directly eastward across the prairies.
Today’s highways, while not following their trails directly, certainly
parallel them to a great degree.
Little is known today of these early adventurers. A few written accounts
have been printed, meager records of their catches have been noted, and
here and there crude initials and dates carved on isolated canyon walls
attest their passing. Their conquest of the West has faded into oblivion
but it must be regarded as the opening wedge of American progress into
the Southwest.
_Mountains as Wildlife Reservoirs_
Today’s traveler spans in hours distances across these same routes that
took weary weeks of heartbreaking toil a century ago. As he rides in
cushioned ease he seldom pauses to reflect on the changes that have
taken place since those early days. The great herds of bison with their
attendant packs of wolves have vanished and in their place white-faced
cattle graze on the level prairies. In the foothills the pronghorns have
taken their last stand. Cities have sprung up on the camping sites of
nomadic tribes that roamed the whole area between the Mississippi River
and the Rocky Mountains. Only the mountains seem the same.
In winter these massive ranges form a barrier against the storms that
sweep in from the northwest. More important—these great storehouses of
our natural resources that in early days meant only gold and furs, and
perhaps sudden death to the pioneers, have now been unlocked by their
descendants. The glitter of gold and the glamour of furs pales when
contrasted with the untold values that have since been taken out in the
baser metals and lumber. This phase too is now coming to an end. It is
becoming evident that in the face of our ever increasing population
these natural playgrounds are destined to become a buffer against the
tensions that we, as one of the most highly civilized peoples of the
world, undergo in our daily life. Within another century they will
represent one of the few remaining opportunities for many millions of
Americans to get close to nature. As such the proper development and
preservation of mountainous areas and their values is of vital
importance to our Nation.
Mountains of the Southwestern States have been formed by three major
agencies. These are, in order of importance, shrinkage of the earth’s
interior to form wrinkles on the surface; faulting, with subsequent
erosion of exposed surfaces; and volcanic action. The first method is
responsible for most of the large ranges, such as the coastal mountains
of California and the Rocky Mountains. Faulting is responsible for many
of the high plateau areas where one side may be a high rim or cliff and
the other a gently sloping incline. The Mogollon Rim, extending across a
part of Arizona and into New Mexico, is a classic example in this
category. Volcanic action may result in great masses of igneous rock
being extruded through cracks in the earth’s surface or it may take the
form of violent outbursts in one comparatively small area. Several
mountain regions in Arizona and New Mexico are covered with huge fields
of extruded lava. Capulin Mountain in New Mexico is an example of a
recent volcano which built up an almost perfect cone of cinders and
lava. Less noticeable than the mountains, but important nevertheless,
are the tablelands of the Southwest. These mesas, too high to be typical
of the desert, and in most cases too low to be considered as mountains,
partake of the characteristics of both.
_Desert “Islands”_
The mountains of the Southwest have been compared to islands rising
above the surface of a sea of desert. This is an apt comparison for not
only do they differ materially from the hot, low desert in climate, but
also in flora and fauna. Few species of either plants or animals living
at these higher altitudes could survive conditions on the desert floor
with any more success than land animals could take to the open sea.
Their death from heat and aridity would only be more prolonged than that
by drowning. Thus certain species isolated on mountain peaks are often
as restricted in range as though they actually were surrounded by water.
At times this results in such striking adaptation to local conditions
that some common species become hardly recognizable. This is the
exception to the rule however; most of the animals in this book are
either of the same species as those in the Northern States or so closely
allied that to the casual observer they will seem the same. Conditions
that enable these species ordinarily associated with the snowy plains of
the Midwest and the conifer forests of the North to live in the hot
Southwest are brought about either directly or indirectly by altitude.
_Life Zones_
There are in this nucleus of four States a total of six life zones, (See
map on page x.) The two lowest, the Lower and Upper Sonoran Life Zones,
range from sea level to a maximum elevation of about 7000 feet. These
two have been covered in the book “Mammals of the Southwest Deserts.”
The remaining four—Transition, Canadian, Hudsonian, and Alpine Life
Zones—will furnish the material for this book. The names of these zones
are self explanatory, because they are descriptive of those regions
whose climates they approximate. Unlike the two life zones of the
desert, which merge almost imperceptibly together, these upper zones are
more sharply defined. They may often be identified at a great distance
by their distinctive plant growth. It should be noted that plant species
are even more susceptible to environmental factors than animals and are
restricted to well defined areas within the extremes of temperature and
moisture best suited to their individual needs. Thus each life zone has
its typical plant species, and since animals in turn are dependent on
certain plants for food or cover, one can often predict many of the
species to be found in an individual area.
The Transition Life Zone in the Southwest usually lies at an altitude of
between 7000 and 8000 feet. It encompasses the change from low trees and
shrubs of the open desert to dense forest of the higher elevations. It
is characterized by open forests of ponderosa pine usually intermingled
with scattered thickets of Gambel oak. These trees are of a brighter
green than the desert growth but do not compare with the deeper color of
the firs that grow at a higher elevation.
The Canadian Life Zone begins at an altitude of about 8000 feet and
extends to approximately 9500 feet. The Douglas-fir must be considered
the outstanding species in this zone although the brilliant autumn color
of quaking aspens provides more spectacular identification of this area
during the fall. Through the winter months when this tree has shed its
leaves, the groves show up as gray patches among the dark green firs. At
this elevation there is considerable snow during winter and
correspondingly heavy rainfall in summer months. Under these favorable
conditions there is usually a colorful display of wildflowers late in
the spring.
The Hudsonian Life Zone is marked by a noticeable decrease in numbers of
plant species. At this altitude, (9500 to 11,500 feet), the winters are
severe and summers of short duration. This is the zone of white fir
which grows tall and slim so to better shed its seasonal burden of snow
and sleet. In the more sheltered places spruce finds a habitat suited to
its needs. Near the upper edge of the Hudsonian Life Zone the trees
become stunted and misshapen and finally disappear entirely. This is
timberline; the beginning of the Alpine Life Zone, or as it often
called, the Arctic-Alpine Life Zone.
Here is a world of barren rock and biting cold. At 12,000 feet and above
the eternal snows lie deep on the peaks. Yet, even though at first
glance there seems to be little evidence of life of any kind, a close
scrutiny will reveal low mat-like plants growing among the exposed rocks
and tiny paths leading to burrows in the rock slides. Among the larger
mammals there are few other than the mountain sheep that can endure the
rigors of this inhospitable region.
These are the zones of the Southwest uplands. Altitudes given are
approximate and apply to such mountain ranges as the San Francisco Peaks
of Arizona and the Sangre de Cristo Mountains in New Mexico. As one
travels farther north the zones descend ever lower until in the Far
North the Arctic-Alpine Life Zone is found at sea level. Since climate
more than any other factor, determines the types of plants and animals
that can live in a given area it is only natural that on these mountain
islands many species entirely foreign to the surrounding deserts are
found at home. Though it would seem that because of the relative
abundance of water at higher elevations the upland species would have
the better environment, this is not entirely true. Balanced against this
advantage are the severe winters which, in addition to freezing
temperatures, usher in a period of deep snows and famine. Even though
many species show a high degree of adaptation to these conditions, an
especially long or cold winter season will result in the death of weaker
individuals.
_Man and Wilderness_
The effects of man’s presence on the upland species is perhaps not as
serious as on those of the desert. Though he has been instrumental in
upsetting the balance of nature everywhere, it has been chiefly through
agriculture and grazing. Because of the rough broken character of much
high country in the Southwest the first is impossible in many cases and
the second only partially successful. There are other factors however
which menace the future of the upland species. Among these are: hunting
pressures, predator control, and lumbering. Even fire control, admirable
as it may be for human purposes, disrupts the long cycles which are a
normal part of plant and animal succession in forested areas. These are
only a few of the means by which man deliberately or unconsciously
decimates the animal population. They are set down as a reminder that
unless conservation and science cooperate in management problems, it is
conceivable that many of our common species could well become extinct
within the next 100 years. Our natural resources are our heritage; let
us not waste the substance of our trust.
As our wilderness areas shrink it seems that our people are gradually
becoming more interested, not only in the welfare of our native species
but in their ways as well. This type of curiosity augurs well for the
future of our remaining wild creatures. In times past an interest in
mammals was limited mainly to sportsmen who often knew a great deal
about where to find game animals and how to pursue them. Their interest
usually ended with the shot that brought the quarry down. Today many
people have discovered that a study of the habits of any animal in its
native habitat is a fascinating out-of-doors hobby in a virtually
untouched field. With patience and attention to details the layman will
occasionally discover facts about the daily life of some common species
that have escaped the attention of our foremost naturalists. This is no
criticism of the scientific approach. It is recommended that for his own
benefit the nature enthusiast learn a few of the fundamentals of
zoology, particularly of classification and taxonomy, which mean the
grouping and naming of species.
_Classification of Animals_
Classification of animals is easy to understand. Briefly, they are
divided into large groups called _orders_. These are further divided
into _genera_, and the genera in turn contain one or more _species_.
Scientific names of animals are always given in Latin. Written in this
universal language they are intelligible to all scientists, regardless
of nationality. It is a mistake to shy away from them because they are
cumbersome and unfamiliar to the eye. They usually reveal some important
characteristic of the animal they stand for. This is their true
function; it seems to this writer that it is a mistake to name an animal
after a geographical location or a person, although it is frequently
done. The literal translations of specific names in this book will
illustrate this point. See how much more interesting and how much more
easily remembered those names are which describe habits or physical
attributes of the creature.
Described herein are but a part of the species native to the
Southwestern uplands. Those chosen were selected because they are either
common, rare, or unusually interesting. Collectively they make up a
representative cross section of the mammals that live above the deserts
of the Southwest.
For further information on these and other mammals of the region see the
list of references on page 123.
HOOFED ANIMALS
_Artiodactyla_
(_even-toed hoofed animals_)
This order includes all of the hoofed animals native to the United
States. These are the mammals which are ordinarily spoken of as the
“cloven-hoofed animals.” An odd-toed group (_Perissodactyla_), which
includes the so-called wild horses and burros, cannot properly be
included as natives since these animals date back only to the time of
the Spanish conquest of our Southwest. In earlier geologic ages horses
ranged this continent, but in more primitive forms than those now found
in other parts of the world.
Through a study of fossil forms it has been determined that our present
hoofed animals evolved from creatures which lived on the edges of the
great tropical swamps that once covered large areas of our present land
masses. They were long-legged and splay-footed, well adapted to an
environment of deep mud and lush vegetation. As the waters gradually
disappeared and the animals were forced to take to dry land, their
strange feet underwent a slow transformation. Because they had become
accustomed to walking on the tips of their toes to stay up out of the
mud, the first toe did not touch solid ground at all in this new
environment. Since it was of no use it soon vanished entirely or became
vestigial. Some species developed a divided foot in which the second and
third toes and the fourth and fifth toes combined respectively to bear
the animal’s weight. Eventually the third and fourth toes assumed this
responsibility alone, and the second and fifth toes became dew claws.
These are the cloven-hoofed animals of today. In other species the third
toe was developed to bear the weight, and this resulted in a single-toed
group of which the horse is an example. In all cases an enormous
modification of the nails or claws with which most animals are equipped
has resulted in that protective covering called the hoof. The under
surface of the foot is somewhat softer and corresponds to the heavy pad
that protects the bottom of a dog’s toe. This brief explanation refers
only in the broadest sense to the order as represented in the United
States. The feet of the various species have become so specialized to
their separate ways of life that an individual can usually be easily
identified by its tracks alone. It is quite possible that many species
are still undergoing subtle changes in this respect.
With but one exception the cloven-hoofed animals of our southwestern
mountains bear either horns or antlers. The exception is the collared
peccary, “javelina,” (_pecari tajacu_) which, during the heat of the
summer, sometimes ascends to the Transition Life Zone in southern
Arizona and southwestern New Mexico. Essentially an animal of the low
desert, it will not be included in this book. The species which have
hollow, permanent horns are the bighorn and pronghorn. The pronghorn is
distinctive in shedding the sheaths of its horns each year, but the
hollow, bony core remains intact. In this group both sexes bear horns.
Animals bearing antlers are the elk and the deer. The antlers are
deciduous, being shed each year at about the same time as the winter
coat. Only the males of these species have antlers, any female with
antlers can be considered abnormal.
The Southwest is fortunate in still having a number of the species of
this order native to the United States. The bison can hardly be
considered a wild species, since it exists now only through the efforts
of a few conservationists who brought it back from virtual extinction.
Mountain goats, caribou, and moose are the only other species not known
to inhabit the Southwest.
In Nature’s balance the order _Artiodactyla_ seems to have been meant as
food for the large predators. Their protection against the flesh eaters
consists mainly in fleetness of foot, keen hearing, and a wide range of
vision, as evidenced by the large eyes set in the sides of the head.
They are but poorly equipped to actively resist attack by the larger
carnivores. Their best defense is flight.
Bighorn (mountain sheep)
_Ovis canadensis_ (Latin: a sheep from Canada)
Range: This species, with its several varieties, inhabits most of the
mountainous region of the western United States. In Mexico it occurs in
the northern Sierra Madres and over almost the whole length of Baja
California.
[Illustration: Habitat map]
Habitat: Among or in the vicinity of more precipitous places in the
mountains.
Description: A blocky animal, rather large, with heavy, curving horns.
Total length of adult male 5 feet. Tail about 5 inches. Weight up to 275
pounds. General color a dark gray to brown with lighter areas underneath
belly and inside of legs. The rump patch is much lighter than any other
part of the body; in most cases it can be described as white. Females
are similar in appearance to the males except that they are smaller and
the horns are much shorter and slimmer. Young, one or two, twins being
common.
Interesting as the desert varieties of this species may be in their
adaptation to an environment that seems foreign to their nature, they
cannot compare with the high mountain animal. Seen against the backdrop
of a great gray cliff or silhouetted against the skyline of a snowy
crest the bighorn has a magnificence that is thrilling. In flight it is
even more spectacular as it bounds from one narrow shelf to another in
an incredible show of surefootedness. Yet this airy grace is exhibited
by a chunky animal that often weighs well over 200 pounds. The secret
lies in the specially adapted hooves with bottoms that cling to smooth
surfaces like crepe rubber and edges that cut into snow and ice or gain
a purchase on the smallest projections of the rocks. The legs and body,
though heavy, are well proportioned and so extremely well muscled that
no matter what demands are placed on them this sheep seems to have a
comfortable reserve of power. No doubt the display of complete
coordination adds to the illusion of ease with which it ascends to the
most inaccessible places. Descents often are even more spectacular, the
animal seldom hesitating at vertical leaps of 15 feet or more down from
one narrow ledge to another.
[Illustration: bighorn]
In the high mountains where this sheep prefers to make its home it
usually ranges near or above timberline. During winter storms it may
sometimes be forced down into the shelter of the forests, but as soon as
conditions warrant it will go back to its world of barren rocks and
snow. Here, with an unobstructed view, its keen eyes can pick out the
stealthy movements of the mountain lion, the only mammal predator
capable of making any serious inroads on its numbers. It has few other
natural enemies. A golden eagle occasionally may strike a lamb and knock
it from a ledge, or a high ranging bobcat or lynx may be lucky enough to
snatch a very young one away from its mother, but these are rare
occurrences.
Bighorns depend mainly on browse for food. This is only natural since in
the high altitudes they frequent little grass can be found. Usually
there is some abundance of low shrubs growing in crevices on the rocks,
however, and many of the tiny annuals are also searched out during the
short summer season. At times a sheltered cove on the south exposure of
a mountain will become filled with such shrubs as the snowberry, and the
sheep take full advantage of such situations. As a rule they keep well
fed for, scanty though it seems, there are few competitors for the food
supply above timberline.
I have observed these sheep many times in the Rockies. Perhaps my most
memorable experience with this species was on Mount Cochran in southern
Montana. It was a gray, blustery day in September with occasional snow
flurries sweeping about the summits. On the eastern exposure of the
mountain a steep slope of slide rock extended for perhaps 1,000 feet
from one of the upper ridges to timberline. Not expecting to see any
game at that elevation, I made my way up this slope with no effort to
keep quiet. In my progress several rocks were dislodged and went
rattling down across the mass of talus. At the summit of the ridge a low
escarpment made a convenient windbreak against the gale that was tearing
the clouds to shreds as they came drifting up the opposite slope, and I
sat down to catch my breath before entering its full force. As I sat
there surveying the scene spread out below, my attention was attracted
by a low cough close by. Looking to the left about 40 feet away and 15
feet above me, I saw two magnificent rams standing on a projecting point
looking down at me. They seemed to have no fear; rather they evinced a
deep curiosity as to what strange animal this was that had wandered into
their domain. For the better part of a half hour I hardly dared breathe
for fear of frightening them. At first they gazed at me fixedly,
occasionally giving a low snorting cough and stamping their feet. Then
as I did not move, they would wheel about and change positions,
sometimes taking a long look over the mountains before bringing their
attention back. Finally when the cold had penetrated to my very bones, I
stood up. They were away in a flash, reappearing from behind their
vantage point with two ewes and an almost full-grown lamb following
them. While I watched they dashed at a sheer cliff that reared up to the
summit, and with hardly slackening speed bounded up its face until they
were lost in the clouds.
Although this happened in 1928 the experience is as vivid in my mind as
though it happened yesterday. Perhaps the most striking feature of
bighorns seen at this close range is the eyes. They might be described
as a clear, golden amber with a long oval, velvety black pupil. Credited
with telescopic vision, they must be some of the most useful as well as
beautiful eyes to be found in the animal kingdom.
Pronghorn (antelope)
_Antilocapra americana_ (Latin: antelope and goat, American)
Range: West Texas, eastern Colorado and central Wyoming to southern
California and western Nevada, and from southern Saskatchewan south into
northern Mexico.
[Illustration: Habitat map]
Habitat: Grasslands of mesas and prairies, mostly in the Upper Sonoran
Zone.
Description: A white and tan colored animal, considerably smaller than a
deer; horns with a single flat prong curving forward. Total length about
4 feet. Tail about 6 inches. Average weight 100 to 125 pounds. Color,
tan or black shading to white under belly and insides of legs. Two
conspicuous white bands under the neck, and the large white rump patch
of erectile hairs are unlike the markings of any other native animal. A
short, stiff mane of dark hairs follows the back of the neck from ears
to shoulders. Hooves black, horns also black except for the light tips
on those of older males. Both sexes horned. Young, usually two, born in
May.
[Illustration: pronghorn]
Pronghorns are unique among cloven-hoofed animals of the Southwest.
There is only one species, with several subspecies; a variety
_mexicana_, once common along the Mexican border, is considered extinct
in this country. The pronghorn has no “dew claws” like most other
animals with divided hooves. It has permanent bony cores in its horns
but sheds the outer sheaths each year. When these drop off the
succeeding sheaths are already well developed. Although at first these
new sheaths are soft and covered with a scanty growth of short stiff
hairs, corresponding to the velvet in antlered animals, it does not take
long for them to harden and become dangerous weapons. They reach full
development at about the time of the rut; bucks have been known to fight
to the death in the savage encounters that break out at this time.
Were it not for its unusual horns the pronghorn probably would be known
by a common name such as the white-tailed antelope, for the beautiful
white rump patch is undoubtedly its next most conspicuous feature.
However, at least two other animals have been named “antelope” because
their posteriors have some similarity. They are the white-tailed ground
squirrel and the antelope jackrabbit of the Sonoran Life Zone. The
ground squirrel (_Citellus leucurus_) has merely a white ventral surface
on its tail which may or may not act as a flashing signal when flipped
about, but the antelope jackrabbit (_Lepus alleni_) has a rump patch
that bears a striking likeness to the pronghorn’s both in appearance and
manner of use. In both cases the rump patches are composed of long,
erectile white hairs which are raised when the animal is alarmed. In
flight they are thought to act as warning signals; at any rate they are
very effective in catching the eye, and on the open plains the
pronghorn’s can be seen at a distance where the rest of the animal is
indistinguishable. It may well be, on the other hand, that this flashy
ornament is meant to attract the attention of an enemy and lead it in
pursuit of an adult individual rather than allowing it to discover the
helpless young. Neither animal can be matched in speed on level ground
by any native four-footed predator.
In times past the pronghorn usually lived in the valley and prairie
country. In the Southwest it roamed over much of both the Upper and
Lower Sonoran Life Zones, wherever suitable grass and herbage could be
found. On the prairies of the Midwest bands of pronghorns grazed in
close proximity to herds of buffalo. During the middle of the last
century it was the only animal whose numbers even approached those of
the latter. More adaptable than the buffalo, it has retreated before the
advance of civilization and taken up new ranges in rough and broken
country which is unsuited to agriculture. As a rule this is much higher
than its former range. Pronghorns are no longer found in the Lower
Sonoran Life Zone, except as small bands that have been introduced from
farther north. The greatest population now ranges in the upper portions
of the Upper Sonoran and along the lower fringe of the Transition Life
Zone. The animal has always been considered migratory to some extent
because it moved from mesa summer ranges to the protection of warmer
valleys during winter months. This habit is even more pronounced in
later years at the higher levels it now inhabits. These slim,
long-legged creatures are virtually helpless in deep snow and avoid it
whenever possible. They have even been known to mingle with cattle and
join with them at the feed racks during severe winters, an indication of
the extreme need to which shy pronghorns are sometimes reduced.
They are essentially grazing animals. In the past they ate prairie
grasses during the summer; in winter these same grasses made excellent
hay that lost little in nourishment from having dried on the roots. In
addition, they ate low herbage and nibbled leaves, buds, and fruits from
shrubs that grew along the watercourses. Their food today is much the
same except that in the many areas where they receive competition from
range cattle they undoubtedly resort to more browse than formerly.
Natural enemies of the pronghorn are legion, their success indifferent.
Every large carnivore will snap at the chance to take one, and even the
golden eagle has been known to kill them. The most serious depredations
are carried out on those young too small to follow the mother. However,
these attacks are fraught with danger, for the females are very
courageous in the defense of their young and at times several will join
in routing an enemy. In addition to this protection accorded them by
adult members of the band, the young have an almost perfect camouflage
in their plain coats that blend so closely with the color of the grass
in which they usually lie concealed. Because of their fleetness, few
adults fall prey to predators. Many attempts have been made to clock the
speed of the pronghorn in full flight but the estimates vary greatly.
Although a fast horse can keep up with one on smooth, level ground, it
is soon outdistanced on stony soil or in rough country.
[Illustration: baby pronghorn]
Bison (buffalo)
_Bison bison_ (Teutonic name given to this animal)
Range: At present bison exist only in widely scattered sanctuaries. In
Colonial times they ranged from southern Alaska to the Texas plains,
from the Rocky Mountains to the Atlantic, and as far south as Georgia.
They are known in historic times in Utah, Colorado, and New Mexico.
[Illustration: Habitat map]
Habitat: Mainly grasslands; a comparatively small number known locally
as “wood” bison lived in the fringes of the forests.
Description: Although bison are familiar to almost everyone, some
figures on weights and dimensions may be surprising. Bulls weigh up to
1800 lbs., reach 6 feet height at the shoulders and up to 11 feet in
length, of which about 2 feet is the short tail. Cows average much
smaller from 800 to 1000 pounds, and rarely over 7 feet long. Both sexes
have heavy, black, sharply curving horns, tapering quickly to a point,
and a heavy growth of woolly hair covering most of the head and
forequarters. A large hump lies over the latter and descends sharply to
the neck. The head is massive, horns widely spaced, and small eyes set
far apart. A heavy “goatee” swings from the lower jaw. All these
features combine to give the animal a most ponderous appearance.
Nevertheless, bison are surprisingly agile and are not creatures with
which to trifle, especially in the breeding season, when bulls will
charge with little provocation. Like most wild cattle, bison normally
bear but one calf per year. Twins are uncommon.
The history of the bison is unique in the annals of American mammalogy.
It hinges on simple economics, reflecting transfer of the western
prairies from Indian control to white. It is a pitifully short history
in its final stages, requiring only 50 years to drive a massive species,
numbering in the millions, from a well balanced existence to near
extinction. Yet considering the nature of civilization and progress
there could have been no other end, so perhaps it is well that it was
quickly over.
For countless centuries the bison had roamed the prairies, their
seasonal migrations making eddies in the great herds that darkened the
plains. They were host to the Indian, and to the gray wolf, yet so well
were they adapted to their life that these depredations were merely
normal inroads on their numbers. They drifted with the seasons and the
weather cycles, grazing on the nutritious grasses of the prairie.
Weather and food supply; these were the main factors which controlled
the “buffalo” population until the coming of the white man.
The first white man to see an American bison is thought to have been
Cortez, who in 1521 wrote of such an animal in Montezuma’s collection of
animals. This menagerie was kept in the Aztec capitol on the site of
what is now Mexico City. There the bison was an exotic, hundreds of
miles south of its range. In 1540 Coronado found the Zuni Indians in
northern New Mexico using bison hides, and a short distance northeast of
that point encountered the species on the great plains. The eastern edge
of the Rio Grande Valley in New Mexico seems to have been the western
limit of bison in the Southwest. Unfavorable climate, plus the
comparatively heavy Indian population of the valley probably combined to
halt farther penetration in that direction.
From 1540 until 1840 the white man limited his activities on the western
plains to exploring. American colonization had reached the Mississippi
River, but remained there while gathering its forces for the expansion
which later settled the West. Under Mexican rule, the Southwest
progressed very slowly. Then in the span of 50 years a chain of events
occurred which determined the destiny of the West and sealed the fate of
the bison herd.
[Illustration: bison]
Outstanding among these events were: the War with Mexico, 1844; the 1849
Gold Rush to California; the Gadsden Purchase in 1854; and completion of
the transcontinental railroad in 1868. The first three added new and
important territory to the United States. This made construction of
transportation and communication facilities a vital necessity, hence the
railroad. Completion of the Union Pacific Railroad in 1868 divided the
bison population into southern and northern herds and made market
hunting profitable. Three factors contributed to extermination: profit
in the traffic of hides, meat, and bones; control of troublesome Indian
tribes through elimination of one of their major sources of food; and
finally, removal of any competition on the grassy plains of Texas and
Kansas against the great herds of Longhorn cattle which were beginning
to make Western range history. In 1874, only 6 years after completion of
the Union Pacific, the slaughter of the southern herd was complete. It
is of interest to note that not one piece of legislation was passed to
protect the southern herd.
The northern herd did slightly better. Closed seasons were established
in Idaho in 1864, in Wyoming in 1871, Montana in 1872, Nebraska in 1875,
Colorado in 1877, New Mexico in 1880, North and South Dakota in 1883.
Nevertheless, the herd dwindled, and by 1890 was nearly extinct. Since
that time, through careful management, a few small herds have been
established in Parks and refuges, but today the bison must be considered
more a domesticated animal than a wild one.
Although the animal was not as important economically to the
southwestern as to the plains Indians, it was a religious symbol of some
value. Archeological finds far west of the historic range, and dances
still used in ceremonies, reveal that several southwestern tribes sent
hunting parties eastward into bison country. This must have been very
dangerous, for plains Indians would have considered them invaders. Bison
were food, shelter, and clothing to them. Imagine their consternation
when white men began to slaughter the source of their living.
There are today but few reminders of the great herds of the west.
Perhaps one well versed in the ways of these wild cattle could still
find traces of the deeply cut trails which led to the watering places,
or shallow depressions where the clumsy beasts once wallowed in the mud.
Many of the Indian dances recall the importance of this animal to
primitive man. Perhaps our most constant reminder is the coin which
commemorates this symbol of the wild west, showing the Indian on one
side and the bison on the other.
Mule deer
_Odocoileus hemionus_ (Greek: odous, tooth and koilus, hollow. Greek:
hemionus, mule)
Range: Western half of North America from Central Canada to central
Mexico.
[Illustration: Habitat map]
Habitat: Forests and brushy areas from near sea level to lower edge of
the Alpine Life Zone.
Description: A large-eared deer with a tail that is either all black
above or black tipped. Total length of an average adult about 6 feet.
Tail about 8 inches. The coat is reddish in summer and blue-gray in
winter. Under parts and insides of legs lighter in color. Some forms of
this species have a white rump patch, others none. The tail may be
black-tipped, or black over the whole dorsal surface, but is more
sparsely haired than that of other native deer and is naked over at
least part of the under surface. Only the bucks have antlers. These are
typical in forking equally from the main beam. They are shed every year.
[Illustration: mule deer]
The mule deer is typical of the western mountains. Even in early days it
was never found east of the Mississippi and now is seldom seen east of
the Rockies. Only one species is recognized in the United States,
although over its vast range are many subspecific forms. All are notable
for the size of their ears, from which derives the common name “mule.”
The black-tailed deer of the Pacific Coast, long considered a distinct
species, is now rated a subspecies of the mule deer.
In a general way the deer of the United States may be divided into two
groups, these separated geographically by the Continental Divide. East
of this line is the territory occupied by the white-tailed group;
westward of it live the mule deer. Inasmuch as species seldom stop
abruptly at geographical lines, we find in this instance that a
whitetail subspecies, locally known as the Sonora fantail, is found
along the Mexican border as far west as the Colorado River, territory
also occupied by desert-dwelling mule deer. In like fashion the mule
deer of the Rocky Mountains can even now be seen in the Badlands of
North Dakota, several hundred miles east of the Continental Divide and
well within the western range of the plains white-tailed.
Though the two species mingle in places, they are easily distinguished
from each other, even by the novice. Because in many cases the animal is
seen only in flight, the manner of running is perhaps the most prominent
field difference. The mule deer, adapted to living in rough country,
bounds away in stiff-legged jumps that look rather awkward on the level
but can carry it up a steep incline with surprising speed. The
white-tailed, on the other hand, stretches out and runs at a bobbing
gallop. Deer seldom take leisurely flight from a human, usually
straining every muscle to leave their enemy as soon as possible. In the
rough, broken country frequented by mule deer this tactic often makes
considerable commotion.
I am reminded of a herd of an estimated 70 deer that I jumped on a steep
mountainside in southern Utah. The crashing of brush, crackling of
hooves, and noise of rocks kicked loose in their flight created the
impression of a landslide.
Another easily seen field difference between mule and white-tailed deer
is the dark, short-haired tail of the former as compared with the great
white fan of the latter. The tail of the mule deer seems in no way to be
used as a signal. In flight it is not wagged from side to side as is
that of the white-tailed.
Antlers of the mule deer are unlike those of any other large game
species inhabiting their range. They are impressively large as a rule
and, because of the high angle at which they rise from the head, often
look larger. The spread is wide in proportion to the height; thus it is
not unusual for a well-antlered buck to be mistaken for an elk,
especially at a distance. The antlers are unique in having a beam that
forks equally to form the points. Thus a typical head might have five
points, these being: the basal snag, a small tine rising from the beam
near the head; and four points, two from the forking of each division of
the beam. The western manner of counting the points consists of
numbering those of one antler only; the method often used in the East
counts all of the points of both. The number of points does not
necessarily denote the age of a deer. Under normal conditions the
antlers will increase in size and points with every new pair until
maturity is attained. They will then grow to approximately the same size
for several years. In old age, the antler development will usually
dwindle with each succeeding year until, in senility, they may be as
small as those of a young deer. The condition of teeth and hooves is a
more accurate indication of age even though this method lacks prestige
of the time-honored system of points.
It would seem, from the ease with which this big deer can be established
in varying types of habitat, that it is in little danger of extinction.
It is probable that the various subspecies will disappear before long
because their range is rapidly being taken up by agriculture or
lumbering. Given some protection, the species will endure in the higher
mountains for many years to come.
White-tailed deer
_Odocoileus virginianus_ (Greek: odous, tooth and koilus, hollow. Latin:
of Virginia)
[Illustration: white-tailed deer]
Range: Mostly east of the Continental Divide in the United States, north
into southern Canada, and most of Mexico except Baja California.
[Illustration: Habitat map]
Habitat: Brushy and wooded country.
Description: A deer with a large, white tail, held aloft and wagged from
side to side as it runs away through the underbrush. In the Southwest,
two geographic variants occur, the subspecies _virginianus_ and the
subspecies _couesi_; the latter known locally as Sonora fantail, and
seen in the United States only in a limited range along the border.
_Odocoileus virginianus_ of the Southwest is a large deer. It usually
weighs between 150 and 250 pounds, and sometimes up to 300. The average
adult animal will measure around 6 feet in total length. Tail about 10
inches. Color is reddish in summer, changing to gray with the winter
coat. Belly, insides of legs, and undersurface of tail are white. Ears
are small. Antlers have upright tines from a single beam.
As the specific name indicates, this is the same deer that is found in
the Eastern States. It is also known as the plains whitetail, because it
was once common along brushy draws and river bottoms throughout the
prairie regions. Preeminently an eastern animal, it occurs most
abundantly in the Eastern States, dwindling in numbers westward to the
Continental Divide. A few scattered groups are found in the Pacific
Northwest, and the subspecies _couesi_ extends westward along the
Mexican border to the Colorado River.
The white-tailed deer may be distinguished from mule deer by any of
three characteristics, all readily apparent in the field. These are:
shape and construction of antlers, size and color of tail, and method of
running. Antlers consist of two main beams which, after rising from the
head, curve forward almost at right angles with a line drawn from
forehead to nose. The tines rise from these main beams. In the mule deer
the beams rise at a higher angle from the head and fork rather than
remain single. The white-tailed tail is long and bushy, fully haired all
around and pure white beneath. In flight it is erected and “wigwagged”
from side to side. This, together with the white insides of the hams,
presents a great show of white hair as the animal retreats. The mule
deer has a thin, sparsely-haired tail that is bare underneath and does
not wave from side to side in running. The “whitetail” runs at a brisk
gallop with belly close to the ground; the mule deer bounds away with a
series of ballet-like leaps.
This is the deer that contributed so much to the pioneers in their
westward trek from the Atlantic States. It was important not only for
its flesh but for its hide, which after tanning became the buckskin
moccasins, breeches, and coats commonly worn by outdoorsmen in early
days. Its distribution is now spotty compared with the former range,
although there are today probably more white-tailed deer in the United
States than in colonial times. This is mainly because in the thickly
settled Eastern States predators have been reduced to a minimum and
hunting seasons carefully regulated. It is too early yet to know if
predator elimination will result in an inferior strain of deer, but the
relative overpopulation in many localities has been indicated by lack of
browse, disease, and excessive winter kill. The latter especially has
been a problem in some of the Northern States. “Whitetails” are
gregarious creatures, banding together in considerable numbers at times,
especially during winter. A band of them in deep snow will stay together
and their hooves will soon tramp down the snow over a small area. As
succeeding snows fall, the drifts become deeper around the “deer yards”
and eventually the occupants become as imprisoned by this white barrier
as though they were fenced. If the number of animals in the yard is too
great, available browse soon disappears and many will starve to death
before warm weather returns. Over most of the mountainous area occupied
by white-tailed deer in the Southwest snow is no problem. The herds
merely move down to lower country when the snow gets too deep. This
seasonal movement is so pronounced that this deer is classed as a
migratory animal in some localities.
In line with this migratory tendency the “whitetail” follows a varied
but well-marked routine in its life pattern. About the time of shedding
the winter coat late in the spring, the bucks also cast their antlers.
With the loss of these beautiful weapons their personalities suffer.
They leave the group with which they have spent the winter and ascend to
the higher mountains, there to consort with a few similarly afflicted
individuals until a new growth of antlers restores their dignity. The
does, left behind, have problems of their own. These include driving the
yearling fawns away to fend for themselves in order that the does may
give undivided attention to the tiny, spotted newcomers that arrive in
midsummer. By this time the adults have put on the short, yellowish-red
summer coat. The fawns are reddish too, but covered with pale spots, a
combination that blends well with lights and shadows in the brushy
places where the does choose to hide them. As soon as the fawns are
large enough to follow their mothers the little family groups begin a
gradual trek up the mountainside. There are several reasons for this
exodus, chief of which are cooler temperatures, better browse, and fewer
stinging insects.
While the does have been rearing their young, the bucks have been
staging a slow comeback on the ridges above. By early fall their new
antlers have hardened, been cleaned of velvet, and polished in the
brushy thickets. With restored weapons they again seek company of the
does. The season of the rut comes in a time when the bucks are at the
peak of vigor and combativeness. Yearlings and weaker bucks are soon
outclassed, leaving the most virile and aggressive males to become
progenitors of the following year’s fawns. The simplicity of this system
is equalled only by its effectiveness. Natural selective breeding is one
of the most important items in perpetuation of a species. A decline in
numbers of the best breeding animals often results in an inferior
strain. In conservation of deer herds it is well to remember that it is
not always the _number_ of animals that is the prime consideration. A
smaller group of healthy, vigorous individuals is usually more to be
desired than a larger population in average condition.
Although the species has vanished from many of its haunts in the Prairie
States, it will not likely become extinct for a long time. Ranked by
many authorities as our foremost game animal, it has been the “guinea
pig” in many conservation experiments. Adaptable to almost any
environment with suitable shelter and browse factors, it needs only a
little protection to become well established. The “key” deer of the
Florida Everglades, a tiny animal attaining a weight of only 50 pounds,
is, however, on the verge of extinction. Another subspecies, the “Sonora
fantail,” native to Mexico and the southwestern United States, is
greatly reduced in numbers and seems destined to vanish.
Elk
_Cervus canadensis_ (Latin: stag or deer, from Canada)
Range: Along the Rocky Mountains of the United States and Canada. Also
found in central Canada, western Oregon and Washington, central
California, and various small areas in those Western States where it has
been introduced.
[Illustration: Habitat map]
Habitat: Wooded places and high sheltered mountain valleys.
Description: A very large deer with enormous antlers, a thin neck, and a
light rump patch. Total length 80 to 100 inches. Tail 4 to 5 inches.
Shoulder height 49 to 59 inches. Average weight 600 to 700 pounds, with
a maximum of about 1100. Coat dark in summer, lighter in winter. Longer
hair on neck and throat of the bull forms a mane that is distinguishable
at some distance. Antlers extremely large, usually six points on adult
males. Females do not normally bear antlers. Hooves are black. Young
usually one, although twins not rare.
The elk is the largest member of the deer family native to the
southwestern United States. It was once widely distributed, known not
only throughout the Middle West but also in most of the Eastern States.
In fact, one of its common names, “wapiti,” is of eastern American
Indian origin; it was so called by the Algonquins. The Crees of Canada
and the Northern States call it “wapitiu” (pale white) to distinguish it
from the darker colored moose with which it was associated in that
region. It is now confined to the Rockies and westward in the United
States, and to the Rockies and central portion of Canada. Many herds now
found in Western States have been introduced to take the place of those
thoughtlessly exterminated in the early days. This has been the case in
Arizona and New Mexico, where Merriam’s elk disappeared before 1900.
This elk, now known only from scanty records and a few mounted heads and
skulls, was a giant of its kind. Not only was it larger than the Wyoming
elk which now takes its place, but it had correspondingly massive
antlers. Its passing is a grim warning of what could happen easily to
the tule elk, a pygmy elk of central California which has been reduced
to a dangerously small herd. The elk now present in the Southwest,
chiefly if not all, are descendants of individuals brought down from the
large herds of the Yellowstone Park area. In their new homeland they
maintain the same habits that characterize the species in Wyoming.
Next to buffalo, elk are the most gregarious large mammals in the United
States. The degree to which they band together varies with the seasons
and can be attributed to their migratory instincts. During summer months
the bands are small and widely scattered high in the Transition Life
Zone and even higher at times. With the advent of cold weather they work
their way down to lower country, and winter finds them gathered in
sheltered grassy valleys. This exodus to winter quarters can be one of
the most thrilling sights in Nature. In the north it is not uncommon for
herds of a thousand or more of these stately animals to move into one of
the more favored valleys. They have the instinct so highly developed
among most animals of knowing when a storm is imminent, and the
migration may be completed within a period of 48 hours, or even less if
foul weather is brewing.
The concentration of hundreds of these hungry animals into one small
area creates numerous problems, the most serious being that of feed.
Before the white man came, the elk population was more scattered, and
many winter feeding grounds were available. In those ungrazed areas they
were able to paw down through the snow to the nourishing dry grass
beneath. Large herds must now be fed on hay to avoid winter losses that
would otherwise result. In the Southwest, with its comparatively mild
winters and small population, the animals experience little difficulty
in weathering the storms without human aid. The present herds appear
well established, and with proper conservation measures should be a
valuable part of our wildlife for many years to come.
[Illustration: elk]
Migratory though they are, elk still must weather a great seasonal range
of temperature. In adapting to these changes they have developed two
definite coats, one for summer and one for winter. The winter garb is
put on early in the fall; it consists of a heavy coat of brown woolly
underfur with guard hairs that vary from gray on the sides to almost
black on neck and legs. Old bulls tend to be more black and white than
the cows and younger animals. This heavy pelage, often called the “gray”
coat, effectively wards off cold winds that sweep through the mountains
and insulates the wearer against snow that is driven into the outer
surface. In the spring this coat is shed to make way for a light summer
coat. The matted hair falls away in great bunches, and the animals are
unkempt in appearance for 2 months or more. The summer coat is made up
of short, stiff hairs with little underfur. The pelage is glossy when
compared with the harsh guard hairs of the winter coat. In color it is
tawny, appearing reddish at a distance. The rump patch is a light tawny
color in both coats.
With the coming of spring the bulls lose the great antlers which they
have carried through the winter. This takes place through a general
deterioration of the antler base accompanied by some reabsorption of
tissues at that point. The antlers may simply drop off or, in their
weakened condition, be snapped off on contact with low hanging branches.
They are usually shed in March, and by May a new pair begins to grow. As
with the rest of the deer family, a thick growth of velvet covers the
new growth. The first stages look rather ludicrous as the antlers
develop points by successive stages, each tine coming to maturity before
the next begins to grow. Eventually the height of the antlers “catches
up,” so to speak, with the overprominent base. At full maturity,
attained by August, there are few sights so impressive as a bull elk in
the velvet. When this stage is reached the antlers, until now extremely
tender, begin to harden and lose their sense of feeling. The bulls strip
off the velvet by rubbing against branches and brush. Gradually the hard
core emerges, stained a rich brown, except for the tips of the tines
which are a gleaming ivory white. The antlers are so beautifully
symmetrical that they seem graceful despite their size. One of the
largest pairs on record has a length of beam of 64¾ inches and a spread
of 74 inches.
A mature bull usually has six tines on each antler. These have definite
names. The first tine extends forward from the head and is known as the
“brow” tine; the next to it as the “bez” tine. Collectively they are
called the “lifters,” formerly known as “war tines.” The next point
inclines toward the vertical; this is the “trez” tine. The fourth is the
“royal” or “dagger” point, and the terminal fork of the antler forms the
final two points which are called “surroyals.”
Unwieldy as this tremendous rack of antlers appears, the animals handle
them with comparative ease. In the normal walk or trot the body is
carried along smoothly with the nose held up and forward. In this
posture the antlers are well balanced and are carried without undue
strain. In running through brush the nose is lifted still higher; this
throws the antlers farther back along the shoulders, and as the nose
parts the branches they slide along the curving beams without catching
on the tines. Despite these cumbersome impediments, the elk creates less
disturbance than most large forest animals when in flight. Antlers as
weapons of offense are far overrated, for they seldom serve this
function. Males have been severely injured and even killed in fights
among themselves, but these are exceptions, and most fighting is done by
striking with the front feet. If antlers are used it is usually with a
chopping, downward motion that rakes, rather than puncturing the hide of
the opponent.
Despite the fine appearance he presents, the bull elk is not content
merely to be seen, but insists on being heard as well. His vocal effort
is a high, clear, mellow tone commonly known as bugling, although it
seems to have more the quality of a whistle than the sound of a horn.
The call begins on a low note that is sustained for perhaps two seconds
and then rises swiftly for a full octave to a sweet mellow crescendo,
drops by swift degrees to the first note, and dies away. This is
followed by several coughing grunts that can be heard only at close
range. Bugling can be heard for a great distance, and on a clear quiet
evening one of the greatest charms of wilderness camping is to hear this
clear challenge flung out from some nearby ridge. The response is
quickly returned from other hillsides, some so far away as to be mere
whispers in the distance.
Bugling is indulged mainly during the rutting season and lasts from
August to November. During this time it undoubtedly is intended as a
challenge to other bulls and perhaps also to impress the cows with their
lords’ great importance. At other seasons it is heard but infrequently,
and then probably is simply an expression of abundant animal spirits.
Cows have been known to bugle, but this is a rare occurrence.
The single calf is born between mid-May and mid-June. Twins are not
uncommon. At birth the calf will weigh 30 to 40 pounds, and is an
awkward animal. It has a pale brown coat liberally sprinkled with light
spots, and a very prominent rump patch. For several days it remains
hidden in the grass while the mother grazes nearby and keeps constant
vigil. Several times daily she will return to let the calf suckle, but
this is done as hurriedly as possible. Many are the predators that are
only too anxious to catch the little one, such as mountain lions,
wolves, bobcats, coyotes, bears, and even golden eagles. Should the calf
be molested it emits a shrill squeal and the cow charges in with sharp
hooves flashing. She usually is successful in driving away the smaller
predators and sometimes intimidates even the largest with her bristling
show of fury. After the calf is large enough to follow the mother, she
warns it of danger with a hoarse, coughing bark.
The presence of canine teeth in elk is a peculiarity not found in other
American deer. They are of modified form, being bulbous growths without
known function. They occur in both sexes but those in bulls have the
greatest development. At maturity they become highly polished and stain
a light brown.
RODENTS
_Including the Lagomorphs_
(_hares and pikas_)
Rodents are the most numerous mammals of the Southwest. This is not an
unusual condition; they enjoy numerical superiority over other mammals
throughout the world. As a rule rodents are small animals; the largest
to be found in the uplands of the Southwest are the beaver and the
porcupine. Although these two are considerably larger than all others of
the group, they cannot be classed as big animals. Because of the large
number of species represented and the varying conditions under which
they live, rodents have wide differences in physical characteristics.
They can all be identified as belonging to this group, however, by one
common characteristic—that of having long, curving incisors. As a rule
these number two above and two in the lower jaw, the only exception
being the hares and some of their closely allied species. These properly
belong to the order _Lagomorpha_ but will be included here with rodents.
The incisors are deeply set in the jaws, that part above the gums being
a hollow tube filled with pulp. Unlike the incisors of other mammals,
they continue a slow steady growth throughout the life of the animal.
This is a means of compensating for the wear the cutting edges must
undergo. The fronts of these teeth are covered with a heavy coat of
enamel, while the back surfaces are either bare dentine or at best
covered with very thin enamel. The wear thus results in a bevel-edged
surface much like that of a chisel which, with the whetting it receives
during the normal movements of eating, remains sharp. A uniform
sharpening of both upper and lower incisors is assured by a peculiar
arrangement of the hinge of the lower jaw. A more-than-average play in
this ball and socket joint allows the lower incisors to slide either
behind or in front of the uppers so that both sets receive approximately
the same wear on both sides. Should one of the incisors be broken or
otherwise damaged so that normal attrition cannot take place, its
opposite will grow to such a degree that the animal is unable to take
food and then may starve to death. Canine teeth are absent in all
rodents, and premolars are lacking in many species. The large gap thus
left between the narrow incisors and the comparatively massive molars
accounts in part for the wide skull that tapers quickly to the laterally
compressed face so typical of rodent features.
Food habits of the various types of rodents differ to a great degree.
Perhaps the term omnivorous might be applied to most of them because
virtually all rodents will eat insects and meat in addition to the usual
fare of vegetable matter. A few might be classed as insectivorous or
even carnivorous. Some species store up hoards of food against lean
seasons; others eat like gluttons when food is abundant and hibernate
through times of want; still others are equipped to spend the whole year
in a busy search for something to eat.
Habitats are equally diverse. Some species live below the earth, some on
the surface of the ground, at least two species are aquatic, and a few
are arboreal. Regardless of where they live, the great majority are home
builders. They strive to locate their homes in the most protected places
and usually line their nests with soft materials. Outstanding exceptions
are the jackrabbit and the porcupine, both of which lead nomadic lives.
In spite of their secretive habits, rodents suffer a tremendous
mortality. Practically all carnivorous animals, most predatory birds,
and many snakes prey on rodents, and for many of them these persecuted
animals form the chief food. This situation is not as harsh as it might
seem, for most rodents are prolific to a high degree. Elliott Coues
summed up their place in Nature’s balance very aptly: “Yet they have one
obvious part to play,... that of turning grass into flesh, in order that
carnivorous Goths and Vandals may subsist also, and in their turn
proclaim, ‘All flesh is grass.’”
Snowshoe hare
_Lepus americanus_ (Latin: hare ... of America)
Range: Found throughout the greater part of Canada and Alaska with
extensive penetrations into the Southwest in Utah, Colorado, New Mexico,
and western Nevada. Its occurrence in northern California is rather
rare, and is confined to only a few higher mountain ranges.
[Illustration: Habitat map]
Habitat: In the vicinity of streams or in conifer forests in the
Canadian and Hudsonian Life Zones.
Description: A small, chunky hare with medium long ears and large hairy
hind feet. An average individual will have a total length of about 18
inches with a tail less than 2 inches. Hind foot about 6 inches in
length. Summer pelage brown, except feet and belly white, and tail
brownish black above. Winter coat white except for the tips of the ears
which are black. Young, three to six, born in May or June.
The snowshoe hare, found sparingly in mountains of the Southwest, is the
same as that which lives in the muskeg not far from the Arctic Circle.
The climate of the mountain zones is surprisingly like that of the north
country even though the terrain is different. The closest equivalent is
to be found in the brushy borders of mountain streams, and here the
“snowshoes” are most often found. During summer they feed on grasses,
herbs, and leaves of many different shrubs and the tender tips of young
branches. Winter, a period of famine for many animals, is just the
opposite for these large-footed hares. Able to run about on the surface
of snowdrifts, each new snowfall lifts them closer to the tender twigs
that earlier in the year were far above their reach. Clean diagonal cuts
much like those made with a knife mark their depredations and, since
they are hearty eaters, the whole tops of many favorite food shrubs may
be pruned out in one season.
In common with several other hunted creatures and a comparatively few
that hunt, the “snowshoe” undergoes a complete change of color between
its summer and winter coat. The transformation begins when the first
snows are due, and usually the white coat is complete when the snows lie
deep on the mountains. It is not, as was once supposed, a case of the
brown guard hairs turning white, but a molt. The summer guard hairs are
shed and white ones taken their place. The under fur changes color to a
less marked degree. Close to the skin the animal is still brown.
Outwardly it is pure white except for black ear tips. Marvelous as this
protective coloration is, it is not absolute proof against enemies.
There are many, and chief among them are lynxes, bobcats, wolves,
weasels, and great horned owls. In many places in the far north the
snowshoe hare is the chief host of the lynx, their numbers fluctuating
in unison.
[Illustration: snowshoe hare]
Like most other hares the “snowshoe” spends a great share of its leisure
time in a “form.” This is usually nothing more than a well concealed
hollow. The semi-darkness under low hanging evergreens is much favored
by these nocturnal animals for this purpose. They do not, at any time,
frequent burrows, the closest approach to this kind of home being in
winter when they are sometimes completely snowed under. They suffer but
little during severe storms, because their long, fluffy fur is
protection against the cold. Their greatest danger lies in the
possibility of being buried alive in the event of a freezing rain
following the snow.
The young are born in late spring or early summer. They come into the
world amid plushy surroundings indeed. The mother has lined the surface
nest with soft hair pulled from her own coat, and a softer, more
comfortable nursery could hardly be imagined. The little hares are born
fully furred, with eyes open, and usually with the incisor teeth already
through the gums. Their development is rapid, and long before cold
weather arrives they are out on their own.
White-tailed jackrabbit
_Lepus townsendi_ (Latin: hare ... for J. K. Townsend)
Range: North of the Canadian border to the southern portion of Colorado
and Utah, and from the Cascade Mountains east to the Mississippi River.
[Illustration: Habitat map]
Habitat: Plains and open country, in the foothills, and even in the high
mountains. Found in both Upper Sonoran and Transition Life Zones.
Description: A large hare with a white tail and a lanky build, found
usually only in open country. Total length (average) 18 to 24 inches.
Tail up to 4 inches. Ears up to 6 inches in length. Weight 5 to 8
pounds. Color varies with the seasons. The summer coat is buffy gray,
the winter coat is white. The tail, long for a hare, is white throughout
the year. The tips of the ears are black both summer and winter. Young,
three to six in a litter, born in May. There may be a second litter
during late summer. As with all the hare family, the young are well
furred and have their eyes open at birth.
The white-tailed jackrabbit is the largest hare native to the United
States. Its great size is further emphasized by its rangy build and long
legs and ears. Such physical characteristics are usually marks of an
animal that is fiercely pursued by its enemies. This denizen of the open
country is no exception. It is preyed upon by innumerable predators,
including man, the most relentless and cunning of all. Yet its place in
the modern world is still secure, for though it is almost totally
lacking in offensive weapons, Nature has given it defensive advantages
far beyond most other creatures. Perhaps the most important is the
deceptive speed with which it floats across the prairie. Fastest of its
tribe and exceeded in this respect by only one native animal, the
pronghorn, this lanky jackrabbit simply runs away from most pursuit.
Effective though this tactic is, the animal uses it usually as a last
resort, preferring to employ the exact opposite, that of crouching
motionless in an effort to avoid detection. Absolute immobility is
itself an admirable defense, but when augmented by camouflage such as
this creature possesses it is even more effective.
Like most members of the hare family, the white-tailed jackrabbit is
more active at night than during the day. It spends most of the daylight
hours resting in a form that it hollows out under shelter of a low shrub
or large tuft of grass. In summer the tawny coat blends well with the
color of the surroundings, and the winter coat is possibly even more
effective. Then the crouched body resembles nothing more than a mound of
snow; the black tips of the ears suggest black weed stems sticking up
through the white surface.
[Illustration: white-tailed jackrabbit]
Mountain cottontail
_Sylvilagus nuttalli_ (Latin: sylva, wood and Greek: lagos, hare. For
Nuttal)
Range: Western United States but east of the coastal range of mountains.
The northern limits are along the Canadian border; the southern limits
in central Arizona and New Mexico.
[Illustration: Habitat map]
Habitat: Mountains of the west through the Transition and Canadian Life
Zones. Seldom found below the pines.
Description: The “powder puff” tail is the best field characteristic by
which to recognize this rabbit, usually the only cottontail in its range
at the elevations given above. It is one of the largest of its kind,
averaging 12 to 14 inches in total length with the tail less than 2
inches long. Average weights run from 1½ to 3 pounds. Ears are
relatively short and wide for a cottontail. Color varies somewhat with
relation to habitat, but in general it is gray with a faint yellowish
tinge. Darkest areas are about the back and upper sides; under parts are
light to almost white. The winter coat is heavier than the summer, but
much the same color. The underside of the tail is the cottony white so
well known to city and country dwellers alike. From the scanty records
available on the number of young it would seem that three to four
constitute the average litter. Perhaps the higher elevations at which
they live keep them free from many of the predators to which their
lowland cousins succumb, and thus they are able to maintain their
numbers with smaller families.
Though often found in the depths of the forest, these shy rabbits prefer
to live in the brushy thickets that border high mountain meadows and
line the streams. There, in true cottontail fashion, they venture into
the open to feed, always ready at the first sign of danger to scurry
back to safety under tangled branches. Once fairly entered into the maze
of paths that they alone know, there is little danger of capture. There
they can count themselves safe from further pursuit by the larger
predators and have a distinct advantage over those their own size or
smaller. Although so clever at turning and doubling back in their chosen
refuges, they seldom use much evasive action when surprised in the open.
Their first thought seems to be to reach cover in the straightest
possible line, and as a consequence many are snapped up by predators who
not only rely on this behavior but often gain the advantage of a
surprise attack as well.
Food habits are much the same as those of other cottontails, modified to
some extent by the different plant associations with which they are
found. In summer, tender grasses and herbs are the favorite fare, but in
winter when deep snow isolates them from even the taller herbs, these
adaptable animals turn to bark and such small twigs as meet their taste.
At this time even the tips of conifer twigs are often eaten. Access to
this food, which during the summer is usually out of reach, is
facilitated by the growth of long hair on the bottom of the feet,
especially on the hind feet. Though these seasonal “snowshoes” do not
approach those of the Arctic hare in size, they serve very well to
support the lighter cottontails as they move over the soft surface. They
are especially useful when the animal stands on its hind feet to reach
some inviting bit that would be out of reach in the normal crouching
position. During this operation it reaches for food with the mouth
alone; the forepaws cannot be used to gather food, but hang loosely in
front of the body as an aid to balance.
[Illustration: mountain cottontail]
This inability to grasp or handle objects with the front feet is
characteristic of all those animals which in the United States we call
“rabbits.” Though here included with the rodents, the jackrabbits,
snowshoe hares, and cottontails all lack the dexterity with the forepaws
with which the rest of the group is endowed. The structure of the bones
is much like that of the ungulates in that the feet cannot be turned
sideways. Thus front legs are used mainly for running, digging, and
washing the face and ears, a procedure much like that employed by
domestic cats, except that it is carried out with the sides of the paws
rather than the insides of the wrists as Tabby does.
Though it lives in a different habitat than other closely related
species, the mountain cottontail shares many of their habits. It is a
nocturnal animal, seldom seen at large except at dusk or in early
morning hours. During the greater part of the day it seeks refuge under
some brush pile or deep in the recesses of the slide rock. On occasion
it will make itself a form in long grass or under a shrub, but usually
prefers more substantial protection. In areas which are being logged,
cottontails are quick to take advantage of the shelter offered by huge
piles of limbs and debris left by loggers. Later in the season, when the
piles are burned, it is not unusual to see as many as three or four
cottontails scurry from one pile.
Nests for rearing the young are not of such great concern to these
rabbits. Perhaps they instinctively choose places where an enemy would
never expect to find them. Many are mere hollows in tall grass or
shallow burrows in an accumulation of pine needles. They are lined with
soft grasses or needles and hair which the mother pulls from her own
body. More hair and grass fibers are cleverly matted together to form a
loosely woven blanket which she pulls over the nest when she leaves. It
is arranged with such cunning and blends so well with the surrounding
that unless one sees the rabbit leave it is only by accident a nest is
discovered. The three to five young are born blind and naked, but thrive
so well in the warm nest that in about a month they are fully furred and
able to leave. At this age they are extremely playful little creatures,
often indulging in a game much like tag, although to a human observer it
is never quite clear just who is “It.”
In this connection it is interesting to note than among the “hunted”
mammals the play spirit is usually manifested by running games in which
there is little if any physical contact. By contrast, the young of
predators indulge in wrestling games featuring use of teeth and claws,
often beyond the point where fun ceases and anger begins.
Pika
_Ochotona princeps_ (Mongol name of pika ... Latin: chief)
Range: Mountainous areas of the western United States, western Canada,
and southern Alaska. Found in the southwestern United States in Utah,
Colorado and New Mexico.
[Illustration: Habitat map]
Habitat: Talus slopes of the Hudsonian and Alpine Life Zones.
Description: A small animal bearing some resemblance to a guinea pig;
found only among or in the vicinity of rock slides. Total length from 6½
to 8½ inches. No visible tail. Color, gray to brown. Eyes small, ears
large and set well back on head. The front legs are short and are
exceeded but little by the hind legs. They are all quite concealed by
the long hair of the sides. This gives the animal much the appearance of
a mechanical toy as it glides smoothly over the rocks. The soles of the
feet are covered with hair, the only bare spots on the feet being the
pads of the toes. The call is distinctive, the most common being an
“eeh” repeated several times. This sound is shrill, but has a falsetto
quality as though it were being produced during an inhalation. Young
thought to number from three to six.
[Illustration: pika]
Far up on the mountainside, above timberline but below the eternal
snows, a great field of talus rests uneasily on the massive slopes of
bedrock. From a distance it seems merely a smooth gray scar that softens
the otherwise abrupt lift of the summit. A closer inspection reveals it
as a tumbled mass of variously shaped slabs of stone varying from tiny
fragments to huge blocks weighing many tons. Its entire bulk is shot
through with chinks and crevices of every conceivable shape and form.
Here and there a wisp of grass or an occasional stunted shrub has found
a precarious foothold among the slabs. Other low matlike plants occur in
considerable numbers. The only sounds are faint whisperings of wind
among the rocks and a distant sighing from the forest below. Suddenly a
sharp “eeh-eeh” breaks the silence, then all is quiet again. The shrill
sounds are repeated, this time from a different quarter. You look toward
the sound but see nothing. Finally, if you are lucky, your eyes focus on
a little face somewhat resembling that of a tiny cottontail rabbit,
peering at you from the safety of a home among the rocks. It is the pika
you see and this rock slide is his castle.
The pika bears a superficial facial resemblance to the rabbit, to which
it is most nearly related. This is occasioned no doubt by the long silky
whiskers and deeply cleft upper lip, for the eyes are small and the
ears, while large, are shaped much differently from those of its larger
relative. Its other physical characteristics are entirely unlike those
of the rabbit. The chunky body, short legs, and almost total lack of a
tail are more like those of the guinea pig to which it is more distantly
allied. Several species are known. All are inhabitants of the Northern
Hemisphere and all, whether Asiatic, European, or American, are found
living in rock slides at or above timberline. In the western United
States the pika is known by a variety of other common names of which
“coney,” “little chief hare,” and “rock rabbit” are perhaps the best
known.
Living as it does in only one type of habitat, the pika has developed
highly specialized habits. The most remarkable is its practice of
cutting hay for winter food. At timberline the growing season is short,
but the herbs and grasses which this animal eats spring up and mature in
a matter of weeks. During this time the pika lives high on the succulent
leaves and stems, but during the latter part of the season it carefully
harvests enough food to last through the coming winter. None of this
hoard is carried directly into the burrow. Instead, it is painstakingly
transported to suitable areas which are exposed to the hot sun, and
there piled in miniature haycocks and left to cure. No human harvester
ever worked harder to gather his crop or laid it up with more care than
this tiny husbandman. Fortunately its tastes are not critical; thus,
although the individual plants are scattered, the pika is able to select
a sufficient store from the considerable number of species represented
at this altitude.
In Utah and Colorado the “haying” time arrives with the height of the
summer blooming season. At timberline this usually occurs during August.
As though realizing that a hard frost would ruin its delightfully
fragrant crop, the pika sets furiously to work. After cutting down as
much herbage as it can handle at one time, it gathers the mass into an
unwieldy bundle and carries it by mouth to one of the sites it has
selected as a curing place. Usually these areas have been used the
previous season for the same purpose, and a mass of the least edible
stems remain to mark their location. Depositing the load on this base,
the pika scurries away for another bundle. Long familiarity with routes
across the uneven rocks enables it to make its way with never a misstep,
even though the load carried may be of such size that vision to the
front is completely obscured. Working early and late the pika
distributes its harvest among the various piles. As a result, the hay
dries out evenly and when cold weather calls a halt to the work each
little stack is perfectly cured without a trace of mildew. The truly
monumental work to which this little creature goes is shown by as many
as a half dozen haycocks, each of which may contain up to a bushel or
more of feed.
Comparatively little is known of the pika’s life history. What has been
recorded has been noted during those periods when it was seen on the
surfaces of rock slides. What goes on deep in the labyrinths of its
habitat can only be conjectured. It seems reasonable to suppose that in
some subterranean cavity the pika has constructed a comfortable nest
lined with soft grasses. Certainly it remains active all winter,
although buried under many feet of snow, for in the spring its stacks of
hay have been largely consumed.
The number of young is thought to range from three to six. They probably
are born in early summer, as when they appear on the surface, usually in
late July or early August, they are about half grown. Though family ties
are closely knit until the young mature, pikas cannot be considered
gregarious animals. The scarcity of food alone would be sufficient
reason to prohibit large groups in one small area. Each adult takes up
squatter’s rights on a territory large enough to support it, and
thereafter holds it with but little interference from others of its
kind.
Few natural enemies prey on the pikas. The very openness of their
habitat prevents the larger predators from stealing up unseen. Hawks and
eagles account for some, and weasels are able to penetrate their
underground maze at will, but the natural fecundity of the species seems
to balance these losses very well. To the nature student the pika offers
a tempting challenge. It is far from being a rare animal, yet at the
same time it is one about which almost nothing is known. As
qualifications for learning its secrets, one must be somewhat of a miner
and considerable of an arctic explorer.
Tassel-eared squirrel (Abert’s)
_Sciurus aberti_ (Latin: shade-tail ... for Col. J. J. Abert)
Range: Northern Arizona, northwestern New Mexico, extreme southeastern
Utah, and south central Colorado in the United States; also found in the
Sierra Madre Mountains of northern Mexico.
[Illustration: Habitat map]
Habitat: Ponderosa pine forests of the Transition Life Zone.
Description: The only squirrels in the United States that have
conspicuous pencils of hair on the tips of the ears. _Sciurus aberti_ is
a large squirrel with a total length of about 20 inches. Tail about 9
inches. The summer pelage is brown on the back, with gray sides and pure
white underparts. The beautiful bushy tail is silvery below and gray
above. During summer the long ears have no tassels on the tips.
Beautiful as is the summer coat, it is far surpassed by the winter one.
Then the heavier fur becomes richer brown on the back, and the contrast
between the gray and white areas is further emphasized by appearance of
a narrow black band between them. The ears too become more spectacular
with the addition of the penciled tufts which give this animal its
common name. Breeding habits of this squirrel are variable and evidently
depend to a great extent on the food supply. There may be as many as two
litters in a fruitful year and none at all in a lean year. The usual
number is three or four young to a litter. These are born sometimes in a
hollow tree, but more often in a bulky nest of leaves built in a tree
top.
No mammal of the United States has a more appropriate generic name than
the large tree squirrel. _Sciurus_ literally translated means
“shade-tail” and refers of course to the beautiful and useful appendage
sported by all of our arboreal types of squirrels. It is doubtful if any
can equal the striking plume carried by _aberti_; certainly none can
surpass it. Its distinctiveness is not occasioned by its size, for
several species have tails that are longer. Rather, its elegance is
derived from the width, the striking coloration, and the easy grace with
which the animal displays its beauty. Whether in full flight across a
grassy clearing or in repose on some lofty limb, the first field mark of
this unusual squirrel will be the tail; the second, the tasseled ears.
As the map shows, _Sciurus aberti_ and its many forms are confined in
the United States mainly to the high country along parts of the Colorado
River, and also to that great escarpment known as the Mogollon Rim,
whose length is divided about equally between New Mexico and Arizona. In
this range is found what is often referred to as the “greatest unbroken
stand of ponderosa pine to be found in this country.” Of the many
species of plants and animals found as associates of this forest,
perhaps none is more dependent on ponderosa pine than the tassel-eared
squirrel. This rough-barked tree furnishes a major source of food and
shelter. In return, for Nature always demands that restitution be made,
the squirrels plant a part of the seeds that insure continuation of the
ponderosas.
It is a common belief that squirrel’s diet consists of nuts and little
else. This is true only to a degree. A squirrel is fond of nuts and will
eat and hoard them during the short season when they are available. For
the greater part of the year, when its stores have been depleted, it
turns to many other types of food among which are fruit, herbage, leaf
buds, and flowers. Favorite food of the tassel-eared squirrel is, of
course, the large single-winged seeds found under scales of ponderosa
pine cones. Next favored are acorns from the oak that mingles with pine
at the lower edge of the Transition Life Zone. If the season is good,
great quantities of cones and acorns are buried for future use. These
are hidden singly, not in caches, as is the habit of some squirrels. In
the event the squirrel does not return for its hidden stores, some of
the seeds will sprout eventually and take their part in the slow cycle
of growth and decay that is continually going on in the forest.
During months when these favorite foods are scarce, squirrels find the
cambium layer of young pine twigs very acceptable. This is the tender
layer that lies between the wood and the bark. In the growing season it
is especially sweet and nutritious. This was as well known to the
Indians as the squirrels, and they too took advantage of the supply
during times of famine. The squirrel obtains this food by cutting off
the terminal clusters of needles, then severing a denuded portion of the
branch, of a size that may be conveniently carried to a favorite eating
place. Here the outer bark is deftly removed, the edible portions
consumed, and the base wood cast to the ground. Although large numbers
of the terminal twigs are taken, the trees seem to suffer no serious
damage from this seasonal pruning.
[Illustration: tassel-eared squirrel]
In selecting a nesting site the tassel-eared squirrel turns again to its
favorite tree, the ponderosa pine. Because few of these healthy giants
have knotholes or cavities of a size to accommodate this large species,
the nests are usually built in the thick upper growth of branches.
Material for their construction consists of small twigs of deciduous
trees, cut with the leaves on them. These are cleverly woven together so
that as the leaves wither and dry they tend to hold the bulky mass
together. Aspen branches frequently are used when available, the large,
almost round leaves combining to form a warm wall and at the same time a
thatch impervious to all but the most driving rains. Several exits are
provided in case an enemy should enter the nest, and the interior is
lined with soft fibers. Usually more than one nest is built by each
squirrel, so that in an area where they are common the bulky homes are
conspicuous not only for their size but by reason of their numbers. With
several ports in a storm, so to speak, the squirrels weather the winter
very well. During the coldest days they remain snugly curled up in their
nests, but on bright, still days they will be seen searching out their
hoarded supplies, even though they may have to dig through several
inches of snow to get to them. At such time their gruff bark, deep in
timbre, may be heard for a considerable distance.
Breeding takes place in early spring, often before the snow is off. The
squirrels are fully polygamous, which is one of the reasons this species
can almost disappear and then restores its numbers within a season or
two. There may be two litters each year, the first arriving as early as
May and the second in August or September. As mentioned before, this
species is variable and the young may differ in coloration from their
parents and from each other. Melanistic individuals are frequent; these
should not be confused with the Kaibab squirrel which they resemble
superficially. Several subspecific forms are recognized but are not
easily identified by the layman.
One’s first introduction to this beautiful species is an experience long
to be remembered. It was no less interesting to the early naturalists
who first penetrated the wild regions where it lived. Their accounts
abound with adjectives such as, “handsome,” “graceful,” etc. Dr. S. W.
Woodhouse, who accompanied the Sitgreaves expedition on the exploration
of the Zuni and Colorado Rivers, noticed it at once and formally
described it as a species in 1852. Since that time it has been
introduced into many of the “sky island,” mountains that lie south of
its original range. It adapts very well to new conditions, seeming to
need only a favorable climate and a ponderosa pine forest in which to
live. What effect its presence will have on these new surroundings is
not yet known. There is always danger that the native plants and animals
will suffer from such new competition in an established association.
Such introductions should never be made without a study of all the
factors involved.
Kaibab squirrel
_Sciurus kaibabensis_ (Latin: shade-tail ... from the Kaibab, a forest
in northern Arizona)
Range: An area approximately 30 × 70 miles in size in northern Arizona.
The southern limit is bounded by the north rim of the Grand Canyon of
the Colorado, and much of the range is included within the boundaries of
Grand Canyon National Park.
[Illustration: Habitat map]
Habitat: Ponderosa pine forests in Canadian and upper Transition Life
Zones.
Description: A tassel-eared squirrel with an _all white_ tail. In size
this species is the same as _Sciurus_ _aberti_ but the coloration is
different. The Kaibab squirrel has the same rich, chestnut brown area
along the back and upper part of the head, but the sides are deep gray
and underparts gray to black. The tail is either all silvery white or it
may have barely discernible light gray edging on the upper surface.
Nesting and breeding habits are the same as with _aberti_.
[Illustration: Kaibab squirrel]
This beautiful squirrel has a distinctive appearance and an uncertain
specific rank. It is included here because of all the mammals discussed
in this booklet it best exemplifies the effects of isolationism. There
is little doubt that the ancestors of both _aberti_ and _kaibabensis_
were of one common stock. How the progenitors of the Kaibab squirrel
came to be marooned on the North Rim of the Grand Canyon is of little
moment. Perhaps they were already there when the Colorado plateau was
young and the river was just beginning its mighty task. Possibly they
emigrated later when the gorge was not as deep as it is now. At any
rate, it can be assumed that they have lived on the North Rim for
thousands of years, isolated from their cousins on the South Rim by only
20 miles of thin air horizontally, but a trip on foot that involves a
descent of a mile through two life zones (Upper Sonoran and Lower
Sonoran), a crossing of a wide and turbulent river, and an ascent to the
South Rim through the same two desert zones. Surely this is an
undertaking for a squirrel of the cool forests that would be too
hazardous to be successful, even if attempted.
The factors that have changed this squirrel’s coloration are not
definitely known, but climatic conditions are probably at least
partially responsible. The North Rim is approximately a thousand feet
higher than the South Rim and is considerably colder. At this higher
elevation much of the Kaibab squirrel’s habitat falls within the
Canadian Life Zone. This in turn makes certain vegetable food available
which is rare or unknown on the South Rim. Thus diet also may have
something to do with its unusual appearance.
At various times the Kaibab squirrel has been known as a distinct
species, _Sciurus kaibabensis_; at others, it has been considered merely
a subspecies of _Sciurus aberti_. The latter is its standing at this
time. Regardless of specific rank, it is a form that should be
stringently protected. The population is small and goes through the same
fluctuations as _Sciurus aberti_. During the summer of 1946 only one
individual was known in the area around Grand Canyon Lodge, where they
usually were found in some numbers. At such times the heedless
destruction of only a few squirrels could conceivably result in the
extermination of this rare and beautiful animal.
Arizona gray squirrel
_Sciurus arizonensis_ (Latin: shade-tail ... of Arizona)
Range: Central to southeastern Arizona and adjacent parts of western New
Mexico in the Upper Sonoran and Transition Life Zones.
[Illustration: Habitat map]
Habitat: Associated with the native black walnuts of canyons, or often
found among the pines on canyon rims.
Description: The common gray tree squirrel to be found in the range
given above. The Arizona gray is a large animal. Total length is from 20
to 24 inches with a large tail accounting for from 10 to 12 inches of
this measurement. In the typical form the color is dark gray above with
underparts and feet pure white. The tail also is dark gray with a
silvery white margin. The finest examples of this species may be found
along the edge of the Mogollon Rim in Arizona and New Mexico. Farther
south the pelage often has a yellowish or brownish tinge. In the
mountains along the border the Arizona gray squirrel should not be
confused with the Mexican fox squirrel (Apache squirrel) which here
barely invades the United States. The Mexican cousin, about the same
size as _Sciurus arizonensis_, is definitely yellowish brown and has
lighter underparts of the same color. Like other large tree squirrels of
the west, the Arizona gray builds a bulky nest of leaves and twigs,
usually in the upper branches of a deciduous tree. Young, four or five
to a litter; under exceptionally favorable conditions two litters may be
reared in one season.
When compared with the royal tribe of Abert’s squirrels, this common
gray animal of the Southwest seems but a peasant. When it is seen alone
comparisons are forgotten. Deliberate in its movements, whether crossing
the forest floor or traveling the leafy aisles of the tree tops, it
seems always to have calculated its next maneuver. The result is a
careless grace that presents the sturdy body and beautiful tail to the
best advantage. Calm in temperament and with but little of the
suspicious nature that is characteristic of the smaller squirrels, the
Arizona gray may easily be tamed in outdoor surroundings and becomes one
of the most satisfactory of wild friends. It is not recommended,
however, that they be fed from the hand or handled at any time.
“Familiarity breeds contempt” is a saying that does not apply to humans
alone. A squirrel’s bite can be serious as well as painful.
Both Mearns and Bailey, who wrote of this species many years ago,
mention it as occurring mostly among the walnut trees of the Upper
Sonoran Life Zone. Perhaps during the intervening years the press of
civilization has driven them from their chosen habitat into a higher
elevation. At any rate, although they still frequent the more isolated
valleys, they are now found also in considerable numbers among the pines
of the Transition Life Zone. The rough broken country along the Mogollon
Rim seems best suited to their requirements, and they are now quite
abundant there.
[Illustration: Arizona gray squirrel]
Along the border of the Upper Sonoran and Transition Life Zones this
adaptable animal finds a wide variety of food. Although the squirrels
generally are known as gatherers and storers of nuts, there are many
other types of vegetable food that they will take when conditions
warrant. The cambium layer of bark and leaf buds of various species of
trees are eaten in spring when nut stores have been depleted. Berries,
fruit, and even flowers form a considerable part of the diet during the
summer. In the fall the ripening crop of pine nuts and walnuts provides
not only food for immediate use but stores for the long winter season
when, unless enough has been laid by, the unfortunate may starve to
death. The gathering period is a time of unremitting labor. From dawn to
dusk the squirrels work feverishly carrying nuts to the hiding places
they have selected. Sometimes these are in a hollow tree or a nest, but
usually the harvest is buried in the humus and debris that collect about
the bases of trees.
There are two phases to the work. In the first the squirrel works in the
tree cutting off the cones or nuts and letting them fall to the ground.
When a considerable number have been thrown down, it descends and
carries them away, one at a time. The latter operation is the most
dangerous since enemies have an undue advantage over this aerialist when
it is on the ground. During the harvest the squirrels plainly show the
effects of their work. In gathering pine cones the fur of their forelegs
and undersides becomes matted with pitch. The juice of walnut fruits
(related to the eastern black walnut, _Juglans nigra_, which the early
pioneers used as a source of dye for coloring their hand-loomed cloth)
stains their underparts a dirty brown. These marks of their labor remain
with them until the summer coat is shed to make way for the heavy winter
pelage.
When the generic name _Sciurus_ (meaning shade-tail) is mentioned, I am
reminded of an Arizona gray squirrel I observed several years ago.
During late fall my wife and I were camped near the headwaters of the
Hassayampa River in a mixed forest of hardwoods and conifers. Our
arrival had interrupted the work of a squirrel which was gathering
walnuts in the immediate vicinity, but he soon became accustomed to our
presence and renewed activities. Every sunny hour he was busy storing
the nuts, many of them at the base of an old pine tree near camp.
Shortly thereafter a fall storm set in and lasted for several days. It
developed into a pattern of misty drizzle followed by periods of
clearing weather when the sun might appear for a few minutes. During
sunny intervals the squirrel would appear, but as soon as it became
overcast again he would as quickly disappear. Finally we discovered his
retreat. When it would threaten more rain he would run up the trunk of
the pine to the first branch. Here he would turn his rump to the hole
and hunch up into a small furry ball with his long bushy tail laid
forward over his back and head and extending down in front of his nose,
forming an admirable protection against the few drops that spattered
down through the thick foliage overhead.
Squirrels are not the only animals who use their bushy tails for
protection against the elements. Many mammals curl up and wrap the tail
around themselves for warmth, but only the squirrel tribe has a tail
long, wide, and flat enough to be used as a roof. Though the origin of
the term _Sciurus_ has been lost, it is not too far fetched to suppose
that it was suggested by a squirrel’s use of its tail as a parasol.
Spruce squirrel, Pine squirrel
(DOUGLAS SQUIRREL, CHICKAREE)
_Tamiasciurus hudsonicus fremonti_ (Greek: tamia, steward and Latin:
sciurus, shade-tail ... of the Hudson, named after Fremont)
[Illustration: spruce squirrel]
Range: Utah, Colorado, Arizona and New Mexico in the Hudsonian and
Canadian Life Zones.
[Illustration: Habitat map]
Habitat: Conifer forests, preferably spruce, in the higher mountains.
Description: A small gray squirrel, usually the only squirrel to be
found at the elevation at which it lives. Total length 13 to 14 inches.
Tail 5 to 6 inches. Two distinct colors of pelage are seasonal. The
winter coat is olive gray to rufous gray above with lighter underparts;
the summer coat is brownish gray to yellowish gray with almost white
belly and feet. A black stripe along the sides is prominent at all
seasons. The tail is narrow and noticeably shorter than the body. It is
gray beneath, rufous gray above, with black border and a black tip.
Little is known of the breeding habits. The four young are born in early
summer and by August are usually out foraging with the mother.
Spruce squirrels (distribution shown in accompanying map) include
several of the more than two dozen varieties of red squirrels in the
United States belonging to the species _hudsonicus_. Combined with
several subspecies of the Douglas squirrels, (species _douglasi_, the
“chickaree” of the far western mountains), they make up the genus
_Tamiasciurus_. This term, a combining form of _Tamias_ (the genus of
chipmunks) and _Sciurus_ (that of squirrels) clearly indicates
relationship of the red squirrels to both groups. It is equally apparent
in the field where the short narrow tail, the black stripe along the
side, and the nervous disposition remind one of the chipmunks, while the
arboreal habits, comparatively large size, and coughing bark are
distinctively squirrel-like.
The spruce squirrel is seldom, if ever, found below an elevation of 6500
feet, and then only in the shady canyons on the northern exposure of
mountains. From this low it will be found up to timberline, or rather
just below that point at which the trees are too stunted to offer the
required protection. It prefers the dense shade of heavily forested
areas, so is rare near the southern limit of its range, and increasingly
common in the northern portion.
In common with the rest of its group, this bright-eyed little animal
keeps well informed on everything that goes on in the territory it has
chosen as its own. Any intruder is thoroughly investigated, then as
thoroughly castigated, and driven out if possible. Since these squirrels
seem to recognize each other’s domain, a trespasser of its own kind
usually leaves at the first sign of trouble. With larger animals and
humans the attack consists of psychological rather than physical
warfare. From a limb at a safe distance above the ground, the doughty
warrior chatters and scolds with increasing vehemence as long as a
passive interest is displayed by the imagined adversary. At the first
threatening movement it disappears in a flash around the opposite side
of the tree. Scratching noises and falling flakes of bark, together with
noises of peevish defiance, indicates that it is working its way up the
trunk. Suddenly it reappears on another limb some distance above the
first and the real show begins. Paroxysms of rage, stamping of feet,
waving of tail, and streams of invective all are meant to show that one
step closer spells trouble. A few squeaks from your pursed lips and this
tremendous bluff gives up to curiosity. In a few minutes the erstwhile
challenger is back on the first limb trying to make out what this
strange creature is about. This amusing procedure can be carried out
over and over again, and usually is, just to observe the stuttering
rages of which this tiny creature is capable. With more considerate
treatment they soon become quite tame, although even then a quick
movement will send them helter skelter to the closest tree.
It is well that this squirrel is a quick and tireless worker. The seeds
it extracts from the spruce cones are so tiny it takes an enormous
number of them to provide that energy. With such a quantity to handle,
it is not so careful in storing the crop as some larger squirrels. A
comparatively few cones are buried in the soft loam beneath the trees;
the rest are stuffed into holes beneath the spreading roots or simply
piled in heaps near the base of the trunk. In a year when cones are
plentiful there may be a bushel or more in one of these piles. With
several such piles within easy reach of the warm nest fastened in the
branches of a nearby conifer, the small harvester has prospects of an
easy winter ahead. Only in the most inclement weather are these active
animals confined to their nests. They keep tunnels open to their
supplies, and each snowfall adds to the security of the caches. All
winter long the stockpiles diminish while the snow beneath some favorite
perch becomes littered with the scales and discarded centers of the
cones. By spring, which comes late at this elevation, the cones are gone
and the squirrel returns to its summer diet of leaf buds, seeds,
berries, mushrooms, and herbs.
The spruce squirrel is the last of what might be called the true
squirrels in this book and, because the group has much in common as
regards food, enemies, and relations to mankind, a short summary might
be in order.
As has been mentioned, the principal diet of these animals is vegetable.
However, all of them, if opportunity offers, will take birds’ eggs and
young birds. This is not intended in any way as a condemnation of the
squirrel tribe. Their inroads on the bird population are what might be
termed “natural losses.” Nature long ago established a norm in bird
reproduction which takes such losses into account.
The enemies of squirrels are legion. From the air, the larger hawks and
owls, and even eagles, are ever alert to swoop in on them. On the ground
lynx, bobcats, foxes, and coyotes take their toll. In northern Utah and
Colorado the marten is one of the most important local controls on the
squirrel population. Fast and powerful, the marten is equally at home on
the ground or in the trees, and it is a fortunate squirrel that can
escape one. The toll taken by all of these predators is high, yet the
natural fecundity of the squirrel is so great that the population
sometimes gets out of hand and disease has to eliminate the surplus.
In their relationship to man the squirrels are among the most remarkable
of our native mammals. It is not ordinarily the purpose of this book to
point out the economic importance of our mammals, but the beneficial
work carried on the squirrels is too important to pass by. One of the
most valuable natural resources that America has is forests. To the arid
Southwest the mantles of living green that cover the mountains are
invaluable. These are sweeping statements, but they are sober facts.
Squirrels play a considerable part in perpetuating this national
heritage. The fact that they do this more or less accidentally merely
serves to call attention to the subtle patterns in which all living
things move to serve one another. Take their simple mechanics of storing
a pine cone, for instance. A hole is dug to a depth of several inches in
the soft duff under a shady conifer. The cone is pushed firmly into the
bottom of the hole and tamped into place with several vigorous shoves of
the nose. Then the hole is carefully filled and smoothed over so that no
marauder will discover it. This procedure may be repeated hundreds of
times by one individual. If the animal never returns (and the rate of
mortality among squirrels is high), the cone can be considered planted.
Not only is it planted at the correct depth and in the most suitable
material for successful germination and growth, but it is full of plump
fertile seeds. Through some instinct the squirrel knows which nuts and
cones are healthy and fully developed. If you doubt this, examine some
of those they have left on the tree. Invariably they will be infested by
insects or “inferior” in some other respect. One of the favorite sources
of pine nuts for reforestation projects in the Northern States is the
stockpiles of the red squirrel. The scales of the cones are tightly
closed when they are taken, but as they open on the drying floor the
healthy, fertile nuts prove the unerring judgment of the harvester.
Northern flying squirrel
_Glaucomys sabrinus_ (Greek: glauco, silvery and Greek: mys, mouse)
Range: Widely distributed throughout most of our Northern States and
Canada. In the section covered by this book, found only in northeastern
and south central Utah, with possible occurrence in northwestern
Colorado.
[Illustration: Habitat map]
Habitat: Associated with conifer forests of Transition to Alpine Life
Zones.
Description: Our only airborne mammal with a long bushy tail. Total
length 9¾ to 11½ inches. Tail 4½ to 5½ inches. Characteristic of this
species is the fold of skin along each side from the fore to the hind
leg. There is considerable color variation in the numerous subspecies of
this squirrel. In general the upper parts vary from dark brown to
cinnamon brown. Sides of face gray; underparts white to pinkish cinnamon
beneath. Hind feet are brown, fore feet gray. The flying membrane is
brownish black above, white to cinnamon beneath. The eyes are large and
dark brown. Young, two to six in a litter, born in spring; a second
litter is sometimes produced in early autumn.
Because flying squirrels are almost entirely nocturnal, they are seldom
seen. This is unfortunate, for they are among the most interesting
forest creatures. Probably more people have seen flying squirrels
through the predations of a house cat than in any other way. Gentle and
unafraid, the squirrels fall easy prey to this night prowler, which
sometimes brings them home to show its owners. Strangely enough, the
victims often are not injured seriously, and if taken from the cat and
allowed to recover from their initial fright they will glide about the
room with much of the grace they display in the wild.
Properly speaking, these squirrels do not fly; that is to say, they are
incapable of sustaining level or ascending flight. Rather they climb to
some height in a tree then launch out and glide to a lower point,
usually the trunk of another tree. As the angle is usually quite sharp
they attain considerable speed. They check this momentum by inclining
upwards just before reaching their objective. This results in a
four-point landing against the tree trunk, sometimes with an impact that
can be heard for some little distance on a quiet night. During these
flights, which may extend 50 yards or more, they are able to change
direction or maneuver against wind currents. This is done by
manipulating the flying membrane and using the tail as a rudder. After a
flight they usually ascend to the safety of the foliage above. They
cannot be considered awkward on the ground, but it is not their chosen
habitat. Flying squirrels are more arboreal than any of our mammals,
excepting a few species of bats.
[Illustration: northern flying squirrel]
Little is known of the habits of this unusual squirrel, but they differ
considerably from those of its relatives who are active during the sunny
hours. Instead of living in a bulky nest hung in tree branches, this
nocturnal aerialist chooses a hollow tree or an abandoned woodpecker’s
hole where the sun’s rays never penetrate. Nests have been found also
under slabs of bark hanging to old lightning-blasted snags. Lined with
soft fibers and shredded bark, they often shelter whole families of
flying squirrels for, unlike the other squirrels, these gentle creatures
get along together. In fact, they might almost be considered gregarious.
Contrary to ordinary squirrel behavior, they never bark or scold. Their
only utterance is a fine whistling squeak, and this is heard usually
only in the nest.
Though delicate in appearance the flying squirrel is extremely hardy. It
is abroad throughout the winter, being confined to its nest only during
stormy weather. It stores food for the winter, but its caches are
usually above ground in hollow trees and crevices rather than buried in
the loam. Their food consists mostly of pine nuts, seeds, and acorns,
but they are also fond of meat. Many a flying squirrel has met its death
trying to take the bait from a trap set for larger game. This taste is
unexplained; it is not known to prey on other animals.
Western chipmunks
Genus _Eutamias_ (Greek: eu, well or good and tamias, steward)
There are at least four species of chipmunks native to the area covered
by this book. Ordinarily but one, or perhaps two, species of a genus
have been chosen for discussion. In this case, however, the chipmunks
are such provocative little creatures and their presence causes so much
interest that all four species will be included, although briefly. Since
the ranges and life zones of some of them overlap in many areas,
positive identification of a species will be difficult in those places,
but in others one species will be dominant or alone. Here the more
subtle characteristics and behavior of that type can be fixed in mind,
and in time it will be less difficult to separate one from the other.
Remember that most of these species have several subspecies. These
generally occur along the upper or lower edges of the life zone
frequented by the type. In the field they are usually indistinguishable
from the type to any but the most practiced observer.
1. Colorado chipmunk (_Eutamias quadrivittatus_)
[Illustration: Colorado chipmunk]
Range: Northern Arizona, northern New Mexico, most of Utah, and all but
the most northern portion of Colorado. This chipmunk lives largely in
the Transition Life Zone. The closely related species _umbrinus_,
commonly called “Uinta chipmunk” inhabits the Canadian and Hudsonian
Life Zones in the Uinta and Wasatch Mountains of northeastern Utah.
[Illustration: _Colorado_]
[Illustration: Uinta chipmunk]
[Illustration: _Uinta_]
2. Gray-necked chipmunk (_Eutamias cinereicollis_)
[Illustration: gray-necked chipmunk]
Range: Central Arizona eastward into southwestern and south central New
Mexico. Total length 7½ to 10 inches. Tail 3½ to 4½ inches. Transition
Life Zone and above. _Neck and shoulders gray._
[Illustration: _Gray-necked, Cliff_]
3. Least chipmunk (_Eutamias minimus_)
[Illustration: least chipmunk]
Range: Western Colorado, western Utah, northern and eastern Arizona,
northern and central New Mexico. Inhabits all zones from Upper Sonoran
to Alpine. Total length 6⅔ to 9 inches. Tail 3 to 4½ inches. _The
smallest chipmunk with proportionally the longest tail. Tail carried
straight up when running._
[Illustration: _Least_]
4. Cliff chipmunk (_Eutamias dorsalis_)
[Illustration: cliff chipmunk]
Range: North and western Utah extending through southeastern Arizona and
western New Mexico. Found mainly in the Upper Sonoran Zone. Total length
8⅘ to 9½ inches. Tail 3⅘ to 4½ inches. _The most indistinctly striped of
any of these chipmunks._
Generally speaking, chipmunks are the link between ground squirrels and
tree squirrels. Physically they have characteristics of both groups, a
combination that is pleasing indeed. A field mark that is a positive
identification of the chipmunk group is the striped face. In addition to
facial stripes, chipmunks also are striped along the back. The pattern
consists of a dark to black median line bordered by two more similar
lines of varying intensity along each side. These fine lines are
separated by broader bands of contrasting color ranging from chestnut to
white. The latter characteristic is shared by several of the ground
squirrels, which often are confused with chipmunks. Predominant colors
of southwestern chipmunks run to rufous, chestnut, and grayish white
with the dark to black lines mentioned above. Underparts are always
considerably lighter than the back. Chipmunks’ tails are usually shorter
than their bodies, flattened horizontally, and short haired when
compared with tree squirrels. All species have cheek pouches of
considerable capacity.
As will be seen from ranges given above, habitat of the chipmunks
encompasses the whole area from sagebrush-covered foothills to
timberline. Their densest population, however, is to be found in thick
forest about midway between these two extremes. Here their bright colors
and sprightly actions do much to enliven somber surroundings. Despite
their wonderful climbing ability, they are most often seen at ground
level or just a little higher. They are fond of areas containing fallen
trees. The prostrate trunks serve admirably as highways for their forays
in search of food, and under the litter which accumulates around them
are many havens into which a hard pressed chipmunk may pop when pursued
by an enemy. The territory appropriated by each of these little
creatures is explored with the most minute care, and all places of
refuge are noted for future emergencies. Any attempt to chase them will
reveal their uncanny memory for these temporary hiding places and that
they are seldom at any great distance from one.
Their permanent homes usually are underground, excavated beneath the
roots of trees or in rocky terrain. At the end of a narrow tunnel a room
of considerable size is worked out. The dirt is often carried out by a
side tunnel, which is permanently plugged with soil when the excavation
is completed. The underground chamber is lined with soft grasses and
fibers as insulation against the cold. At the higher elevations the
ground may freeze to a depth of several feet during the long winters.
Permanent nests are sometimes built in hollow logs, but almost never in
holes in upright trees. Chipmunks have little taste for upstairs
apartments. In addition to the large cavity which contains the nest,
several storage chambers are constructed to hold the winter’s food.
These may be connected to the main apartment by tunnels or may be
entirely independent of living quarters and some distance away. As a
special feature, many of the more elaborate homes have a separate
chamber reserved for sanitary purposes. Like most of our native rodents,
chipmunks are fastidiously clean in their habits.
It is difficult to discuss the habits of a group as large and of such
wide distribution as our southwestern chipmunks in any but a most
superficial manner. In general they are much more terrestrial than
squirrels and prefer brushy, rock terrain to the more open forests
frequented by their larger relatives. Nevertheless, they are adept
climbers and do not hesitate to take to the trees in search of food or
to escape their enemies. These arboreal excursions are usually limited
to one tree; they do not ordinarily attempt the daring leaps from one to
another that are characteristic of the squirrels. They progress quietly
while on the ground, threading their way through the undergrowth so
expertly that their presence is often undetected.
Normally chipmunks are shy creatures at first acquaintance, but if their
friendship is encouraged they often become bold to the point of being
unwelcome. Woe to the camper whose grub box is invaded during his
absence. These tiny opportunists can carry away a surprising amount of
food in a very short while. Their natural diet differs widely according
to habitat. Chipmunks of the foothills eat a great variety of grass
seeds, berries, and cactus fruits. These are possibly the favorite foods
of the whole group, but as the elevation increases this supply becomes
limited and is supplemented by juniper berries, acorns, and pine nuts.
Considerable quantities of these less perishable foods are laid away for
future needs. During the summer months herbage, fungi, small tubers, and
some insects add variety to an otherwise dry menu.
It is doubtful if any southwestern chipmunks enter true hibernation
during the winter. Those of lower elevations are active throughout the
colder months, except when a period of exceptionally inclement weather
will force them to remain underground for a few days. At higher
elevations they will disappear, perhaps for weeks at a time, but it is
assumed they remain active in their underground quarters. The fact that
during the fall they do not lay on a coat of fat, like many species
which are known to hibernate, substantiates this theory.
Breeding habits of chipmunks are not too well known. The number of young
averages from four to six. Those species living at low elevation
sometimes bear two litters each year; those at higher elevations are
limited to one. Like the ground squirrels, the young are able to leave
the burrow when but little more than half grown. At this early age they
present a rather ludicrous appearance with their large heads and
sparsely-haired tails. This is a time of great danger, for the
youngsters are easily caught by predators which would be eluded with
little difficulty by a mature individual. Principal predators of the
chipmunks are bobcats, hawks, foxes, and coyotes. The last two often dig
out the burrows. The marten is possibly their worst enemy, but
fortunately for the chipmunk tribe is a rare animal throughout its
range.
Chipmunks are quite common in several of our southwestern National Parks
and Monuments. Despite signs to the contrary, the public cannot resist
feeding these little beggars, and many are the situations that develop
from this practice. I recall camping at Bryce Canyon National Park where
the least chipmunk is a common resident. Upon our return from Rainbow
Point one day we spied a chipmunk with bulging cheek pouches leaving our
tent for its den somewhere on the edge of the canyon rim. We found that
our visitor had entered the grub box and gnawed a neat hole in the top
of a carton of rice. Although we had been gone but a short time, more
than half the contents had already been carried away. This was a state
of affairs that needed mending so we decided to teach the marauder a
lesson. On his return trip we waited until he had entered the carton and
then clapped a dishtowel over the hole. The cellophane window in the
side of the carton gave us an excellent view of our prisoner.
Interrupted in his pilfering, he at first tried to get out of the carton
but, finding no exit, returned to stuffing his cheek pouches with more
rice. When they were filled to capacity he calmly sat back and returned
stare for stare. In the end we let him go and gave him the rest of the
rice, exacting such payment as we could by taking pictures of his
labors.
Golden-mantled ground squirrel
_Citellus lateralis_ (Latin: citellus, swift, and lateralis, belonging
to the side, referring to the stripe along the side)
Range: Western United States and Canada. In the area covered by this
book to be found in western Colorado, from northeastern Utah south
through central Utah to central Arizona thence east into western New
Mexico.
[Illustration: Habitat map]
Habitat: Higher mountains of this area. Usually found in evergreen
forests of the Transition, Hudsonian, and Canadian Life Zones. It
sometimes occurs near the upper limits of the Upper Sonoran Zone.
Description: A chipmunk-like ground squirrel lacking the stripes along
the sides of the face characteristic of the chipmunks. Total length 8½
to 12½ inches. Tail 2½ to 4½ inches. There is much color variation in
this species. Head coppery to chestnut, upper surfaces of body brownish
gray to buffy. A light to white stripe bordered with black is present on
each side of the back. Under surface of tail gray to yellow. Tail short
but fully haired. Under surfaces of body lighter, gray to buffy gray.
Legs short, body chunky in comparison with chipmunks. Young, four to
eight, with but one litter each year.
The golden-mantled ground squirrel has been chosen from the rather large
group of southwestern ground squirrels because it is most typically a
mountain dwelling species. As such it does not have the advantages of a
long summer season like its lowland relatives. This results in two
definite periods each year. One is feverish activity during summer, a
time of breeding, rearing the young, storing food, and laying on fat for
the cold months ahead. The other in winter is the exact opposite—a long
interval of hibernation when, buried deep under the snow in a snug
burrow, the squirrels sleep away the winter.
Though hampered by the short summers of higher elevations, the
golden-mantled ground squirrels manage to lengthen the season slightly
by a very simple expedient. Instinct prompts them to dig their burrows
on a southern exposure, often under the base of a log or in a rock
slide. Here the snow melts away first and they often have a bare spot of
ground in front of the burrow several weeks in advance of the season.
The squirrels emerge from their long sleep weak and emaciated, and their
first days above ground are spent soaking up the warm sunshine and
waking up, so to speak. During this period they live on stores laid away
the previous summer, and by the time the snow has melted they are fully
active and ready for mating.
[Illustration: golden-mantled ground squirrel]
As with the ground squirrels of lower areas, the summer diet consists
largely of whatever starts to grow first. During late spring, grass,
buds, young leaves, and flowers are eaten. Later, seeds of the annuals
are gathered, berries are taken whenever possible, and insects often
form a considerable part of the diet. As fall comes on, acorns, pine
nuts, and a great number of smaller seeds and fruits become available.
At this time the ground squirrels must not only lay on enough fat to
maintain themselves through hibernation, but must also store away enough
food to tide them over between the time of their emergence and the
appearance of new growth. Evidently this is an adaptation forced upon
them by the exceptionally long winter season. Most rodents which lay on
coats of fat preparatory to hibernation depend almost entirely on it to
carry them through. With a hibernating period of from 5 to 7 months,
however, it is not difficult to realize the problems this ground
squirrel must face.
Though the golden-mantled ground squirrel resembles the chipmunks in
appearance, its temperament is quite different. Chipmunks are bright,
nervous little sprites, always pursuing their activities with explosive
energy. The ground squirrels move more sedately, as though they had
planned every move and there was no hurry. They love to lie in the sun
in some exposed place and watch the rest of the world go by. In habitat,
too, the species differ materially. Chipmunks choose thick undergrowth
where they can go about their business unobserved. Ground squirrels
prefer more exposed locations where they take their chances in the open,
but with one eye always cocked aloft as insurance against attack by hawk
or eagle. Creatures of the earth, they are always reluctant to climb.
Rarely do they ascend more than a few feet, and then only to reach some
especially toothsome delicacy that their keen noses have detected in a
low shrub or small tree.
With its wide distribution, visitors to the southwestern mountains can
hardly fail to notice this golden-headed member of the ground squirrel
family. It is easily tamed; too easily in fact for, like the chipmunk,
it can quickly wear out its welcome. In many of the National Parks and
Monuments they compete with chipmunks for the crumbs around camp sites
and picnic tables. Visitors find their cunning way irresistible and feed
them despite warnings to the contrary. Because they do tame so easily
there is always danger that some well-meaning person will attempt to
pick them up. This can lead to unpleasant results. Their long sharp
incisors can inflict a serious wound.
One of the most fascinating places to observe both chipmunks and these
ground squirrels is from the windows of the long tunnel leading
northward out of Zion National Park. On the talus slopes beneath the
windows a great number of these rodents take up summer quarters,
depending for food on the largesse distributed by visitors as they eat
their picnic lunches on the broad ledges of the windows. Their constant
movements as they run among the rocks seeking stray crumbs result in
many a collision and often an angry dispute as well. This proves a
dangerous game, as rocks sometimes will be loosened by their movements
and roll down the steep incline. I recall seeing a ground squirrel
crushed by one of these miniature rock slides in 1946.
White-tailed prairie dog
_Cynomys gunnisoni_ (Greek: kun, a dog and mys, mouse ... for Captain
Gunnison whose expedition took the type)
[Illustration: white-tailed prairie dog]
Range: Western Colorado and eastern Utah to central Arizona and New
Mexico.
[Illustration: Habitat map]
Habitat: Grassy meadows and mountain parks mainly in the Transition Life
Zone although they are often found both above and below this area.
Description: A ground-dwelling rodent somewhat resembling a ground
squirrel but several times larger than the biggest species of that
genus. Total length 12½ to 15 inches. Tail 2¼ to 2½ inches. Weight 1½ to
2½ pounds. Color buff to cinnamon buff, the short fully-haired tail
tipped with white. Sides of face darker with a dark area over the eyes.
Legs, feet, and underparts pale cinnamon buff. Young, usually five in
number, born in early summer.
_Cynomys gunnisoni_ is the representative species of the western group
of prairie dogs. The two remaining of the group, _Cynomys leucurus_ and
_Cynomys parvidens_, both white-tailed species, are very similar and
possibly will be classified with _Cynomys gunnisoni_ in the future.
_Cynomys leucurus_ is found in northwestern Colorado and northeastern
Utah, while _Cynomys parvidens_ is native to mountainous valleys in
central Utah.
The common name “white-tailed prairie dog” is usually applied to
_Cynomys gunnisoni_, the most widely distributed member of the race. The
range of this species borders on but seldom overlaps that of the
black-tailed prairie dog which lives farther east and at lower
elevation. Climatic and geographic barriers separating these two races
are largely responsible for pronounced differences in their habits.
Prairie dogs are gregarious creatures, perhaps more so than any other
rodent. Formerly the black-tail species inhabited countless thousands of
acres in the Great Plains region. A single colony might occupy an area
several miles in diameter and number many thousands. On this relatively
flat land, every home site was equally advantageous and the grass and
herbage all ideally suited to the prairie dog’s use. Periodic flooding
of their burrows on these level prairies was avoided by building conical
mounds with a rim of earth around the entrance. This ingenious practice,
simple though it seems, represents a long step in the adaptation of
these animals to their environment.
White-tailed prairie dogs, on the other hand, are limited to the narrow
valleys and infrequent open meadows of the mountains. Here there is
neither room nor food to maintain the huge colonies characteristic of
the black-tailed. Under these conditions the number of individuals in a
town will vary from a few to 200, seldom more. If the town becomes
crowded, many of the inhabitants may migrate to some more favorable
location. This sometimes entails a trip of several miles, a hazardous
undertaking for a small animal whose only escape from large predators is
in an underground burrow.
Food of this mountain prairie dog is varied. The standard diet of grass
and roots is augmented with browse, bark, and tubers. Bulbs of mariposas
are taken wherever available. Coarse-leaved annuals such as sunflowers
are not passed by. In addition to this vegetable diet, worms, beetles,
and larvae as well as mature forms of most insects are eaten whenever
possible.
Burrows of white-tailed prairie dogs, though comfortable, are not made
with the painstaking care found in those of the lowland species. There
is no need for a conical mound or built-up rim because there is
virtually no drainage problem on the sloping terrain of the mountains.
Naturally the burrows will not be excavated in the path of flood waters,
but on higher ground. Earth brought out from the underground workings is
piled to one side or in front of the entrance. The mound thus formed is
used as a place to sun bathe or, even more important, as a look-out post
from which to see all that goes on. Because these small colonies do not
have the advantage of numbers, each individual must be especially alert
to approaching danger. Burrows often have more than one entrance, each
with its well-packed sentry post at hand, the underground plan is
simple. It consists of a more or less vertical shaft from which one or
more tunnels extend horizontally. It is common supposition that the
prairie dog digs deeply enough to strike water. This is not so; many
burrows do not go deeper than 6 feet. In any event, they penetrate just
far enough to insure a comfortable average temperature in both summer
and winter. Water requirements of prairie dogs are met largely by the
succulent nature of their food. It is also presumed that during late
summer months when the diet consists to some extent of seeds, a chemical
process within the system transforms some of the starches to water.
The nest is usually situated in an underground room dug at the end of a
tunnel, less often somewhere along its length. It is a bulky structure,
built of shredded bark or coarse grasses and lined with the softest
fibers obtainable. In these modern days prairie dogs do not object to
paper, rags, and wool.
The life of the prairie dog is simple. Early in the spring it emerges
from hibernation, a bit groggy but still well padded with fat. This
nourishment sustains it until the first green shoots of grass appear.
From then on food is obtainable in an ever increasing supply, limited
only by the distance to which these indifferent runners dare venture
from their burrows. Summer is a time of eating, of dozing on the mounds
in the warm sun, and of conversing with neighbors in the shrill barking
whistles characteristic of this group. It is also a time of constant
vigilance against predators, of dust bathing to rid themselves of mites
and fleas, and of rearing the young. The four to six young are born in
late spring and first appear at the burrow entrance when about the size
of an average adult ground squirrel. Within a few days they are foraging
for themselves, and about 3 weeks later are able to make their own way.
At this time the mother frequently deserts them and builds herself a new
burrow, leaving her offspring to divide the old homestead as best they
can. As fall draws near, a thick coat of fat is put on, and by the
middle of October most of the town’s inhabitants have retired for the
long winter’s sleep.
Yellow-bellied marmot (woodchuck)
_Marmota flaviventris_ (Marmota, Dutch name of European species of
woodchuck. Latin: flavus, yellow, and venter, belly)
Range: Northwestern United States. Common in northern to south central
Utah, northern and southeastern Colorado, and extreme north central New
Mexico.
[Illustration: Habitat map]
Habitat: Canadian, Hudsonian, and Alpine Life Zones in rock slides,
rocky hillsides, under rock piles, and around outcroppings in mountain
meadows. Seldom found below the Canadian Zone but often occurring in the
Alpine Zone to the very summits of the mountains.
Description: A large, dark, brown marmot with a comparatively long bushy
tail. Total length 19 to 28 inches. Tail 4½ to 9 inches. Body color,
yellowish brown to dark brown above; under parts yellow. The body fur
has a grizzled appearance. Sides of neck buffy, and sides of face dark
brown to black. Light brown to white between the eyes. The feet are buff
to dark brown. Tail dark brown above, lighter below. Young, five to
eight, born in early summer.
This large western marmot is not too far removed from the ground
squirrels in either relationship or habits. It is the largest
ground-dwelling rodent native to the Southwest. As mentioned above,
marmots occupy a tremendous altitudinal range, reaching from above
timberline down into the Transition Life Zone. This distribution from
arctic to almost desert conditions is responsible for many variations in
their habits. Most important is the practice of estivation by those
individuals which live at the lower elevations. This summer sleep is
used as a defense against that period of drought between rainy seasons.
It usually starts early in June and ends about the latter part of July.
In the higher life zones there is no lack of green food throughout the
summer, consequently marmots there remain active.
Because of large size and ability to make good use of its sharp teeth
and claws, the marmot’s life is not so restricted as that of many
smaller ground-dwelling rodents. It has enemies, to be sure. Bears,
mountain lions, wolves, lynxes, wolverines, and eagles all are alert for
a possible catch. Yet it is so well on guard and has so many burrows
that it is next to impossible to catch one above ground. Should the
marmot be surprised away from a burrow, its bold show of defense often
gains enough time to work its way to a place of safety. When cornered
its appearance alone is enough to make the average predator pause and
consider. With hair standing on end and long claws at the ready, the
marmot clatters its sharp teeth and hisses loudly at the enemy. This
pose is not all bluff. These big rodents are courageous and able
adversaries against any animal up to several times their size. As far as
man is concerned, they are timid and secretive. On many an occasion
their loud, full-toned whistles will be heard, but the whistler will be
nowhere in sight. If cornered, however, they will put up the same
courageous defense they display against other enemies, and certainly are
not animals with which to trifle.
Burrows are usually in open places where a good view of the surroundings
is obtained. Too, they are almost always in clefts of rocks, under
boulders, or in coarse rocky soil. This lessens the probability of their
being dug out by some large predator. Each marmot usually will have
several burrows, some being “escape” means and one a permanent home.
Well-worn trails lead from one to another, for these are active animals
which travel extensively within the limits of their territories. Escape
burrows may be deep or shallow, as circumstances dictate, but the home
burrow generally is a labyrinth of long passages that terminate in a
nest chamber up to 2 feet across. Several auxiliary tunnels are usually
reserved for sanitary purposes. None is used for food storage; records
indicate that this creature does not lay up stores for later use. The
nest is the usual bulky affair, built of coarse materials and lined with
the softest grasses and fibers obtainable.
Late to bed and early to rise is characteristic of the marmots. Classed
as a diurnal animal, they nevertheless travel about a good deal at dusk.
During the breeding season they may even make an extended trip at night
to find a mate. Sunrise signals the beginning of the marmot’s day. The
slanting rays have no more than touched the boulder above its burrow
before the inmate will climb up to take advantage of their warmth. It
may stay atop its vantage point for an hour or more. There are many
things a marmot can attend to while taking the early morning sunbath. A
leisurely toilette, whistled comments to neighbors, a long scrutiny of
the terrain for possible danger—all these are matters requiring thorough
attention.
[Illustration: yellow-bellied marmot]
Should this procedure be interrupted by a prowling enemy, excitement
runs high. If the intruder is still some distance away, the marmot often
will stand up on its hind legs, picket pin fashion. Each explosive
whistle will be accompanied by several flicks of the tail. When it is
judged time to retire it will dash for its burrow, making sharp chirps
as it goes. Once inside the burrow it may chance another look outside,
and if the caller looks menacing enough the burrow entrance will be
plugged with earth from inside, the chirps becoming fainter as the
barricade is forced into place. Emergence from the burrow after a fright
of this kind is governed to some extent by the time of year. If it is
autumn and the marmot is about ready to hibernate, it may go to sleep in
its cozy nest and not reappear until the next day. Even in spring and
summer it will remain underground for a considerable time before
venturing out again.
The marmot is by nature a stocky animal. Short-legged and barrel-bodied,
it can lay on a surprising amount of fat for the period of hibernation.
Length of this winter sleep depends on the elevation at which the animal
lives. On the higher mountain tops it begins about October 1. At lower
elevations it may be considerably later. Older individuals usually go
into hibernation first, presumably because they are able to lay on the
necessary fat sooner than younger ones. As a rule they retire by stages,
disappearing for several days at a time; their movements are lethargic
and they act as if already half asleep. The young of the year have spent
the greater part of the summer growing up, and it is rather a grim race
with time to determine whether they will be able to put on enough fat to
carry them through the long winter with a reserve supply, or whether
they can survive the cold weather that greets them. Especially at the
higher elevations, they do not retire until forced to do so by cold
weather.
Hibernation is as profound with these big rodents as with many of the
ground squirrels. They will curl up into furry balls in their cozy
nests, noses covered with fluffy tails, and sink into a deep sleep that
approaches suspended animation. Bodily functions slow to a fraction of
the normal rate, and the system draws on its store of fat to survive.
The drain on this nourishment is slow, as it necessarily must be, for
this single source of food must last for a period of perhaps 5 months.
The date of emergence varies. Although February 2nd is recognized as
groundhog day on our calendar, this date would be chilly indeed on the
peaks of our Southwest mountains. Nevertheless, the marmots do appear
before the snow is entirely gone, and once their sleep has ended they
rarely resume it, whether or not they see their shadows.
Breeding takes place shortly after emergence. The young are born in
April or May. They are born blind; the eyes do not open until about a
month after birth. The youngsters develop rapidly, and by the time they
are half grown a daily session of sunbathing and playful tussles outside
the entrance of the den is part of their routine. By September they are
fully grown, and at this time they usually strike out for themselves,
although cases have been recorded in which the family remained together
through the first winter’s hibernation.
Marmots have always been favorites of this writer. Their clear-toned
whistle is as much a symbol of the rugged peaks and lovely fir-rimmed
mountain meadows as the coyote’s barks are of the desert. Several
writers characterize marmots as “stupid.” Surely this is an unfortunate
choice of word. Stupid by what standards? Can one species be compared
with another when all must live under the different conditions to which
they have adapted themselves? The mere fact that a balance of Nature has
been attained indicates that each has the adaptations, the habits, and
the degree of intelligence necessary for that species to live in harmony
with the whole.
Deermouse (white-footed mouse)
The genus _Peromyscus_ (Greek: pera, pouch, and muscus, diminutive of
mys, mouse)
[Illustration: deermouse]
Range: All life zones throughout North America.
Habitat: Some species of deermouse can be found in almost any
association imaginable.
Description: A large-eared mouse with white feet. Since there are many
species in this genus and most of them are quite similar,
characteristics common to the greatest number will be given. Bear in
mind that these may not hold true with every species of the genus.
Deermice are rather small, averaging 7 to 8 inches long. Tail 3 to 4
inches. Most species are a buffy gray above shading to brighter buff on
the sides and light buff to white beneath. Feet are always white. The
ears are large for a mouse, usually sparsely covered with short, fine
hairs, but in some species almost naked. Eyes appear black but have a
brownish shade when viewed closely in a good light. Tail long, up to the
length of head and body, as a rule sparsely haired; bicolor in some
species. Young, four to six, born almost any time of the year, with
several litters except at higher elevations where only one litter may be
born, and this during late spring.
In the Southwest the mild climate and plentiful food supply of the lower
life zones combine to attract a great number of small rodents. By far
the greater number of species is found in the Upper and Lower Sonoran
Zones. This does not mean that mice are rare in the high mountains. They
live there in great numbers, but of fewer species. One is the
long-tailed deermouse (_Peromyscus maniculatus_), probably the most
outstanding member of the genus, and the most widely distributed mouse
in the United States. As might be expected, it is quite variable in
appearance, having at least three distinct color phases. These vary from
golden tan to a dark gray. All phases have a sharper bicolor tail, white
beneath and like the rest of the upper body on top.
The deermouse is well known to those who are fortunate enough to own
summer cabins in the mountains. This is the little rodent which moves
into the cabin as soon as the vacationer departs. Fortunately it is not
so destructive as the common house mouse (which, by the way, is an
introduced species) and limits its destructiveness for the most part to
building a large and comfortable nest in which to live during the winter
months. Deermice do not hibernate, so they must prepare against the
bitter cold. However, it is not their habit to store food either, and
doubtless many of them starve to death over a hard winter.
Mountain vole
_Microtus montanus_ (Latin: small ear ... of the mountains)
[Illustration: mountain vole]
Range: The mountainous regions of northwestern United States extending
eastward to central Colorado and southward below the northern borders of
Arizona and New Mexico.
[Illustration: Habitat map]
Habitat: Valleys and grassy meadows seldom lower than the Transition
Zone.
Description: A small sturdy rodent with short tail, total length 5½ to
7½ inches. Tail 1½ to 2½ inches. This is a very short tail for a rodent
of this size, amounting to only about a fourth of the total length.
Color, grayish brown to black above; underparts lighter to a silvery
gray. This is but one of many species found in southwestern mountains.
The Mexican vole and the long-tailed vole are two which share its range.
They are quite similar in appearance and their life histories also are
much the same.
In several ways this heavy-set rodent resembles the pocket gopher. The
small ears and eyes as well as the short tail are all reminiscent of
that animal. Like many other rodents, voles are quite prolific. From
four to eight young are born in a litter. The number of litters each
year depends to a great extent on the altitude. They have been recorded
in the Canadian Zone, where the summers are too short to permit the
rearing of more than one litter. In the Transition Life Zone they
commonly bear two litters and sometimes more each year.
These are the small rodents which most people call “field” or “meadow”
mice. In the prairie states this genus is well known for its habit of
congregating under shocks of small grain and corn. Here they build their
nests and temporarily live in peace and plenty. When the shocks are
taken from the field, they are rudely evicted from their snug shelters
to fall prey to the farmer’s dog or to face the prospect of building a
new home before winter descends upon them. In the West, too, this “field
mouse” makes itself at home in agricultural areas, but its native haunts
are the natural meadows in mountain valleys. Here they build tunnels in
the tangled growth of grass, and excavate shallow burrows in the soft
earth. Marshy places are particularly to their liking, because they are
quite at home in water. Too, the thick cover in these areas gives them
considerable protection from their many enemies. A normally high
reproduction rate (several litters per year with up to eight young in
each litter) coupled with a secretive way of life insures their
perpetuation. In cases where a natural balance has been upset, their
population can soar to fantastic heights. In one agricultural district
in Nevada a survey revealed an estimated 8,000 to 12,000 “field mice”
per acre.
Voles do not hibernate. They are active night and day, summer and
winter. During winter storms they may remain in their snug nests for a
few days at a time, but with the return of clear weather, openings to
their tunnels will soon appear in freshly fallen snow.
Western jumping mouse
_Zapus princeps_ (Greek: za, intensive and pous, foot. Latin: princeps,
chief)
Range: Western United States from central Arizona and New Mexico to
Alaska.
[Illustration: Habitat map]
Habitat: High mountains in dry places with abundant low ground cover.
Description: A small rodent, two-toned in color, that leaps through the
grass much like a kangaroo rat. Total length 8 to 10 inches. Tail 4½ to
6 inches. Color buffy along sides, shading to almost black on the back
and white on the underparts and feet. Tail bi-color, dark above and
light gray beneath. Ears relatively long, dark in color with light buffy
marginal lines. Eyes beady, set in long face with sharp nose. Front legs
short but hind legs and feet large and muscular. Young, four to six in a
litter, with no more than one litter a year in the higher elevations.
The jumping mice are among the most specialized small rodents in the
United States. The genus is typically North American, only one species
being found outside this continent. At some time in the distant past
this little creature adapted itself to a mode of flight much like that
of the kangaroo and jerboa. In this respect it exceeds the kangaroo rats
and pocket mice of the United States, species to which it is distantly
related. Its general build is distinctly like that of the kangaroo, with
the same delicately formed front quarters and heavier hind quarters. The
tail, though not club-shaped like the kangaroo’s, is long enough to
serve the same purpose—that of a rudder to guide the direction of
flight. The hindlegs are muscular enough to propel the body on
proportionally longer jumps than even the kangaroo. Here the resemblance
ceases, however, for the jumping mouse is not related, even distantly,
to this marsupial. The only pouches the jumping mice have are internal
cheek pouches used exclusively for transportation of food.
Jumping mice have one more peculiarity that set them apart from most
other North American mice; they hibernate. The period of hibernation is
not a short one at the elevations at which these mice live. It may last
for as long as 6 months. Preparation for this extensive period of
inactivity consists mainly in gathering and eating grass seeds until a
thick layer of fat is stored under the skin. With the first cold weather
the jumping mice retire to previously prepared underground burrows and
sleep the winter away.
Since they are almost exclusively seed eaters, they may have a difficult
time on emerging in the spring. Apparently there is no food cache stored
away for this period, so the hapless rodents must search for what can be
found until the grasses head out again. The method of harvesting grass
seed is unique, and once seen will not be easily mistaken. Living as
they do in a jungle of tall grass, they are not able to reach the heads
nor to climb the slender stems. Instead, they cut off the stem as high
as they can reach, pull the upper part down to the ground and cut it
again. This goes on until the head is brought within reach. Small piles
of grass stems, all cut to an average length, indicate that this is the
species which has been at work.
Jumping mice seldom will be seen except when in flight. Then their
jack-in-the-box tactics make it almost impossible to determine what they
are really like. They are timid, inoffensive little creatures which, if
caught, will seldom offer to bite.
Bushy-tailed woodrat
_Neotoma cinerea_ (Greek: neos, new and temnien, to cut ... Latin:
cinereus, ashy)
Range: Mountainous portions of western North America from Alaska south
to central California, northern Arizona and New Mexico.
[Illustration: Habitat map]
Habitat: Found usually in association with the pines of the Transition
and Canadian Life Zones; crevices in cliffs and among rock slides are
favorite nesting sites.
Description: This woodrat will be recognized at once by its bushy,
squirrel-like tail. The several other species in the same range have the
usual scanty growth on the tail, so thin as to be almost unnoticeable.
This species is large for a woodrat; total length ranges from 12½ to 18
inches. Tail 5½ to 8 inches. The soft, thick fur shows wide variation in
color, as might be expected from the great range occupied by this
species with its many subspecies. In general it varies from ashy to
cinnamon above, to pure white on the underparts. Although the head has
the same general shape as that of other woodrats, its appearance is
altered somewhat by long, silky whiskers up to 4 inches in length, and
extremely large ears. The dark, beady eyes, however, are typical of the
genus. The young, from two to six, are born in early summer. This
average of four or possibly less, when the breeding habits of all the
subspecies are taken into consideration, seems low when compared with
other small rodents. The low death rate indicated probably is due not
only to this species’ secretive habits but to a high order of native
intelligence as well.
[Illustration: bushy-tailed woodrat]
Many are the names applied to this interesting little animal. “Mountain
rat,” “pack rat,” “trade rat,” and woodrat are some of the most common.
Several stem from the supposition that when the animal takes an article
that suits its fancy, it always replaces it with something which it
supposes to be of equal value. Observation of the creature’s habits will
indicate that these “trades” are entirely by chance. These animals are
continually carrying small objects about and often drop one in favor of
another more to their liking. The fact is that the most attractive items
usually are carried to the vicinity of the nest, and so the scientific
name of one of the subspecies is perhaps one of the most appropriate for
this industrious collector. This subspecific title is _orolestes_, which
translated from the Greek means _oros_, mountain, and _lestes_, robber.
The penchant for carrying away another’s property leads to many
incidents both comic and tragic. The rats are not at all averse to
sharing a prospector’s cabin, and during hours when the rightful owner
is away at work raise havoc with his possessions. During long winter
nights they are no less industrious, and the mysterious sounds of their
activities will keep even a sound sleeper awake for hours. Eventually
this becomes so exasperating that drastic action is called for. One old
prospector told me of a woodrat that had been bothering him for a long
time. Traps proved of no avail and finally one night he placed his
forty-five on a box beside his bed, together with a candle and matches.
During the night he was again awakened and quietly sat up and lighted
the candle. There on one of his cupboard shelves was the dim form of the
rat. Taking careful aim in the flickering candlelight, he pulled the
trigger and hit the animal “dead center.” The heavy slug literally blew
it apart. Unfortunately it happened to be sitting directly in front of a
5-pound can of coffee. One may assume that without either woodrat or
coffee he slept soundly thereafter.
My own experiences with this species have been no less exasperating.
When but a youth, my brother and I were quartered in an old bunkhouse
one winter. We chose the smaller of the two rooms as being easier to
keep warm, and after a thorough clean-up moved in. No rank novices, we
wired our watches to a nail driven into the wall and hung our other
valuables from a wire stretched across the room. In the morning our
socks were missing! Thereafter matters were uneventful for a week. The
woodrat would come up through a hole in the corner of the room as soon
as the lights were out. All night long it would make trips through the
connecting door into the adjoining room and carry away loads of cotton
from an old mattress on the unused bed.
Came the week-end and the Saturday barn dance about 3 miles up the
canyon. Fresh shirts and trousers donned, coats and vests were taken
from the chair backs upon which they had been carefully hung. Behold!
One vest front was completely chewed out and carried away, presumably
for nesting material. This was the last straw; the creature must be done
away with.
On the following night plans were laid with care. Two 5-gallon oil cans
were placed in the doorway. This left a narrow passageway just wide
enough to accommodate a small jump trap. A piece of newspaper was placed
over the trap and the end of the chain wired to the head of the steel
bedstead. A short time after the lights were put out, a scratching noise
indicated that the animal had come in through the hole. All was quiet
until its nose came into contact with one of the empty cans. Then snap!
A series of squeaks and the rattle of the chain gave warning that the
creature was climbing into bed. As it came in over the head, the wildly
excited occupants left by the foot. When the light was struck the rat
was sitting in the middle of the bed. A heavy boot soon dispatched it
and a semblance of order again returned to the bunkhouse. Strange to
say, no more woodrats came in for the remainder of the season.
Although such experiences are the rule when this rat has moved into a
dwelling, it is a delightful creature in its native haunts. It is a rim
rock dweller; that is, it likes best to build its nest far back in some
deep crevice of a cliff. If such a location is not available it may find
a protected site in a talus slope or even among the roots of a tree.
Usually these natural fortresses are further reinforced by the addition
of a pile of sticks and miscellaneous materials piled helter skelter
over the nest. The nest itself is quite large, usually a foot or more in
diameter, built of the softest and warmest materials at hand. Somewhere
adjacent to the nest will be found one or more caches of food against
the time when the snows are deep and famine stalks the land. As has been
mentioned, the woodrat is usually associated with the pines of the
Transition Life Zone and above, and pine nuts are one of its most
popular items of food. Acorns, seeds, berries, stone fruits, and some
vegetation round out its vegetable diet. It will also eat meat whenever
available although, except for insects, shows little inclination to kill
its own. With such a varied menu, it seems entirely proper to call this
rodent omnivorous.
One of the most characteristic marks of the woodrat’s home is a strong,
musky odor. This is not an indication of uncleanliness. The animal is
most fastidious in its toilette but has this body odor in large measure.
A study skin will retain a strong trace of it for many years. Whether it
functions for an identification to others of the species is not known,
but it could well serve this purpose.
Although classed as a nocturnal animal, the bushy-tailed woodrat is
often active throughout the daylight hours. They are not gregarious
creatures; yet, since suitable nesting sites may not be found in some
areas, other more favored localities often will harbor considerable
numbers of the animals. Overhanging ledges may shelter the piles of
litter denoting a nest every few feet. In such cases, a well-worn trail
will lead from one to the other. This is not an indication that a colony
lives there in peace and harmony. These rats are truculent creatures
among themselves, and if a stranger should venture into a nest mound, he
is evicted with many indignant squeaks and a fearsome snapping of teeth.
The interloper seems to know he is out of order and usually leaves the
nest at once without more than a token show of resistance. In neutral
territory such as a cabin, however, several woodrats may share the area
quite peacefully, but to the great annoyance of the human occupant.
The variety of sounds produced by such a group is quite amazing. Added
to the usual high-pitched squeaks and patter of running feet are the
mysterious rustlings of paper and other objects being dragged about. A
peculiar thumping sound indicates a gait which I have never seen but
often heard at night. It must be somewhat like the leaping flight of a
kangaroo rat, at least it indicates a swift succession of leaps across a
flat surface such as a floor or roof. Perhaps the broad surface
presented by the flat of the bushy tail is of assistance in this
maneuver. Then, like most rodents, the woodrat will thump with its hind
legs as an alarm signal. This is perhaps the most noticeable sound of
all, for it marks the instant cessation of all activity for every member
of its kind within hearing distance. The “ear-splitting silence” that
follows this signal literally presses in on one in the darkness.
Muskrat
_Ondatra zibethicus_ (French Canadian word from the Iroquois and Huron
Indian word for muskrat. Latin: the odorous substance of the civet
alluding to the musk secreted by the muskrat)
Range: Virtually all of North America north of the Mexican border.
Muskrats are found from near sea level to as high as 10,000 feet above
it.
[Illustration: Habitat map]
Habitat: This large rodent can exist only near a permanent water supply
which is deep enough to shelter it from its enemies. This may be a lake,
a marsh, or a running stream.
Description: A large aquatic rodent whose long, flat tail undulates from
side to side when it swims. Total length 18 to 25 inches. Tail 8 to 11
inches. Weight 2 to 4 pounds. The thick, dark brown fur of the upper
body is overlaid with brown to black guard hairs. The legs are short but
powerful. The front feet are small, but the hind feet are relatively
large and partially webbed, with stiff hairs on the edges of the webs
and along the sides of the toes. The long, black tail is flattened
vertically. It is so scantily haired that it may be said to be naked,
but is covered with small scales up to 2 millimeters in diameter. The
head is quite similar to that of a vole. The ears are so short as to
barely protrude through the fur, and the eyes are small. Average number
of young thought to be six per litter. Several litters may be born each
year.
The presence of muskrats in a shallow lake or marsh is not difficult to
detect. This is their chosen habitat, and here in water about 1½ feet
deep, they build their characteristic mounds of rushes and cat-tails.
Here they may also be seen on quiet days swimming about and carrying on
their normal activities. In much of the Southwest, however, such
favorite habitats are few and far between and the muskrats must take
their choice, if there be one, between the few permanent streams and
irrigation canals. In these altered circumstances they react quite
differently; they may often be present in considerable numbers without
anyone being the wiser. The change in habits required by this different
environment illustrates the great adaptability exhibited by many of our
most common mammal species.
The most important requirement of a muskrat is a permanent body of water
of a depth sufficient for it to dive into and escape from its enemies.
Given this, it will at once set about constructing a home. In a lake or
marsh, there is little or no current. In sheltered bays, where wave
action is slight, the bottom often will be muddy. In the shallow water
along the shore, water plants such as tules and cattails will become
established. This is indeed muskrat heaven, for these and other aquatic
plants are both their food and building materials. The most edible
portions of the plants are the roots and the stem portions which are
below the surface of the mud. When one of these choice tidbits has been
cut free by the muskrat’s sharp teeth, it is carried to some favorite
place to be eaten. This may be a mud bar well sheltered by overhanging
vegetation from prying eyes, the end of a log projecting above the
surface of the water, or perhaps the roof of the “house.” The discarded
portion of the stem is buoyant and usually lodges among the remaining
plants until needed for building purposes.
[Illustration: muskrat]
When the muskrat house is being built, a great quantity of this flotsam
is piled up until the resultant mound may project as much as 3 feet
above the water and be 5 or 6 feet in diameter. The nest is built above
the waterline in this half-submerged “haystack.” Entrance to the living
quarters is by a tunnel which usually starts through the mud a short
distance from the base of the house, goes under the edge of the
structure, then inclines upward to the nest. Only one entrance is
necessary for even if some enemy should tear through the tangle of
rushes deep enough to reach the nest, it would take so long that every
inmate could easily escape by this submarine route. The house serves one
more important purpose in the far north. When the ice lies thick over
the marsh and seals this water world away from air, the muskrats can
still take short forays under the ice for food and return again to free
air, without which no mammal can exist.
Had the muskrat learned to build dams such as beavers construct, the
species might very well be near extinction in the Southwest, since such
structures would seriously interfere with irrigation. However, since
they have accepted conditions as they are, the muskrats do very well for
themselves in the shallow streams and irrigation ditches. In fact, their
population under the adverse conditions of today is probably far above
that of the days before the white man arrived on the scene. Do not
assume from this statement that a whole new way of life has been opened
up for the muskrat. There has always been a “bank” muskrat that lived in
burrows in the stream banks. This fast-water addict has now taken full
advantage of the artificial streams that are the forerunners of
agriculture almost everywhere in the Southwest. The burrows built into
the canal banks seem to be identical with those constructed under
natural conditions.
The “bank” muskrat builds three types of shelters, each with a definite
and necessary function. These might be called the feeding burrow, the
shelter burrow, and the breeding burrow, respectively. The first two are
simple in design and have few variations, but the breeding burrow may be
extremely complex. If a choice is available, all burrows will be in a
bank along the swiftest flow of water, as on the outside of a curve in
the canal, for instance. This prevents the entrances from silting shut
as they would in the more quiet reaches.
There are two types of feeding burrows. The first and more common
consists of a cut made just above water level in the side of a vertical
bank. If possible, it is behind a portiere of hanging grass or weeds, so
as to be completely screened from view. This is merely a safe place to
which the muskrat can take its food and eat without being bothered by
enemies. The second type of feeding burrow is more elaborate, consisting
of several such chambers along the bank connected by short tunnels.
These seem to be community shelters since they are used by several
individuals at the same time. The added safety provided by the
connecting tunnels seems to be the advantage in this type of dining
room.
The shelter burrow not only affords escape from enemies, but may be a
sleeping burrow as well. It consists of two tunnels which start at
different levels under water and join just before they reach the main
chamber, which of course, is above water level. The two tunnels assure
an escape route if one or the other is invaded by an enemy. Each muskrat
may have several of these shelter burrows. The one used as a sleeping
burrow will be furnished with a soft nest of shredded leaves. Cattail
leaves are a favorite material for this purpose. Wet, green cattail
leaves in a damp underground cavern make a poor bed by most standards,
but no doubt, it seems a dry, cozy retreat to the muskrat as it emerges
dripping from its underwater tunnel.
The breeding burrows are large and elaborate in design. There is reason
to believe they are not always the work of one individual. They may even
represent combined efforts of several generations of muskrats. Often
they are a labyrinth of tunnels connecting many nesting chambers, each
with a nest of different age. This can be determined by the yellowing of
the shredded leaves. As might be expected, there are usually a number of
tunnels leading from this maze into the water. A half dozen of these
underwater entrance tunnels is not unusual. All this room gives the
young a place to exercise before they are able to take to the water.
Young muskrats are surprisingly precocious. They are able to leave the
nest when very small, and at 4 weeks of age are weaned and capable of
taking care of themselves, although only about one-fourth grown. At this
stage, they are peculiar looking little individuals. The fur is still in
the woolly stage, dark and bluish in color. The guard hairs have not yet
appeared, and altogether they have an unkempt appearance. This rapidly
disappears, however, when they leave the burrow. Their progress is so
rapid that young born early in the spring are believed to breed during
the following fall.
Though ordinarily confined to the immediate vicinity of water, muskrats
sometimes are found in amazing places. The urge to travel sometimes
influences them to go across country for many miles to some other body
of water. They may also become overcrowded in an area so that food
becomes scarce and some may leave on that account. It is not uncommon in
the Middle West for them to burrow into a farmer’s root cellar in early
fall and spend months in this haven of warmth and good food before they
are discovered. Floods may carry them many miles away from established
haunts and leave them stranded on high ground when the waters recede. A
muskrat found in this predicament is not an animal with which to trifle.
If it cannot escape by water, it will probably elect to make a stand.
The long, sharp incisors are formidable weapons indeed, and any enemy,
including man, had best allow judgment to become the better part of
valor.
The tracks of muskrats are so characteristic that they cannot be
mistaken for those of any other animal. Strangely enough they resemble
to a striking degree those of certain types of extinct reptiles called
dinosaurs. The tracks of the two small front feet are close together and
overlapped somewhat by those of the larger hind feet. Between the tracks
is the sinuous trail left by the sharp-edged tail.
Beaver
_Castor canadensis_ (Latin: a beaver ... from Canada)
Range: The beaver, like the muskrat, can be found almost everywhere in
North America north of the Mexican border.
[Illustration: Habitat map]
Habitat: Near any water supply of enough volume, with or without
damming, to provide security for a beaver family.
Description: The largest North American rodent; further distinguished by
having a broad flat tail. Total length 34 to 40 inches. Tail 9 to 10
inches. Weight from 30 to 60 pounds. In color the beaver varies from a
deep, rich brown in the northern states to a much paler shade in desert
regions of the Southwest. The soft, rich underfur is partially concealed
by coarse, rather stiff guard hairs. The brown color of the upper parts
shades to a chestnut under the belly and on the inner sides of the legs.
The forefeet are small with well developed claws. They appear naked but
have a scanty cover of coarse hairs. The hind feet are large and webbed,
and are similarly covered with a few coarse hairs.
The body of the beaver has somewhat the appearance of a kangaroo in that
the rear portion is heavy and appear overdeveloped in comparison with
the more stream-lined head and forequarters. Much of this impression is
gained from the heavy, flat tail which is thick and muscular at the
point where it joins the body. One of the most useful appendages
possessed by any creature, the tail is paddled-shaped horizontally and
about an inch thick in the middle, tapering to thin edges and tip. It
appears naked, but is covered with scales.
The young, averaging four in number, are born in the late spring and,
although they are soon able to take care of themselves, the family
remains together for most of the year.
Indications of beavers in an area are their dams or the distinctive
stumps left by their tree felling. Beaver tracks are seldom found.
Although this aquatic animal often leaves the water, and may go a
considerable distance overland, its tracks usually are obliterated by
the passage of the heavy rump and the dragging tail.
The beaver, perhaps as much as any other factor, was instrumental in
opening up western America to civilization. Even before the Thirteen
Original Colonies had become firmly established along the eastern
seaboard, venturesome men were working westward in search of more beaver
to supply the ever-increasing demand for this soft-rich fur. Industrial
empires were founded on this traffic in skins which came from as far
west as the Mississippi River. By the early 1800’s, the trappers had
penetrated to the Rocky Mountains, and in 1806, upon the return of the
Lewis and Clark Expedition from the Pacific Northwest, they swarmed to
the headwaters of the Missouri River system. Prior to this, the
Southwest had been given little attention by the fur industry. It was
considered an inhospitable region, inhabited by hostile Indians, and
with a few settlements of Spanish colonists who, up to that time, had
actively resisted the intrusions of the more aggressive Americans.
However, by the year 1820, relations had improved to such a degree that
a few of these hardy individuals were trapping on the headwaters of the
desert rivers. Later, their activities spread to include the entire
length of these remarkable watercourses.
These were the Mountain Men, a hard-as-nails breed of frontiersmen in a
class by themselves. In the period from 1820-1854, when a large part of
the Southwest became part of the United States through the Gadsden
Purchase, they roamed the plains and mountains of the American Desert.
Their roster includes such legendary figures as Bill Williams, Pauline
Weaver, Kit Carson, and James Pattie. Their argosy was a quest for the
rich, brown beaver pelts which were a golden fleece indeed when
presented to the fur traders in far-off St. Louis. In time, their
moccasined feet beat a broad path across the western plains—a path then
known as the Santa Fe Trail, but identified today as U.S. 66, the “Main
Street of America.”
Today, many of the streams which supported beaver colonies in the desert
places have vanished entirely, and others have been so effectively
harnessed for irrigation and power that there is no place for beavers in
them. In the higher mountains, however, there are many streams remote
from civilization where clear ponds still sparkle in the sunlight, and
the splash and dripping of busy beavers can be heard on quiet, summer
evenings. Because beavers quickly become established under any
conditions which are at all favorable, they have been reintroduced into
numerous places where they had been extinct for many years. Usually this
is good conservation practice, but under some conditions, it may prove a
mistake. Ecologically speaking, beavers probably are the most important
creatures in any animal community of which they are members. This is
because these busy engineers not only impose a tremendous drain on the
surrounding area for material, very often they also radically alter the
character of the terrain to fit their own needs.
[Illustration: beaver]
The life history of the beaver is one of the most interesting of all
mammals. It has been studied for centuries by naturalists in both the
New and Old Worlds, for the beaver, with but few differences, is native
to both. All this study and observation notwithstanding, the habits are
still only partially known. This is because the beaver is mainly a
nocturnal creature which spends most of its daylight hours in the
concealment of a lodge or burrow. Then, too, in the northern latitudes
where the ponds are covered with ice throughout the long winters there
is little opportunity to observe this phase of its existence. There is
but one species of beaver in North America but about two dozen
subspecies. The northern types and those which live in the mountains of
the Southwest seem to be dam builders who live in beaver “lodges.” Those
which inhabited rivers of the lower desert were mostly “bank” beavers
which lived in burrows in the banks of streams. This latter type is rare
today.
Perhaps the best way to understand the ecological importance of the
beaver is through watching the rise and decline of a typical colony.
Picture if you will a small, shallow stream flowing gently down a narrow
valley in the mountains. Bordering the low banks is a thicket of alders.
Back of them a thick growth of aspens extends to the edge of the valley
and mingles with the spruce trees on the slope. Down this slope comes a
young male beaver at a clumsy gallop, his broad tail striking the ground
with an audible thump at every lope. This emigrant has struck out for
himself because the colony to which he belongs has become crowded. He
finds the stream and, since the water is too shallow to conceal him,
crouches under an overhanging bank until darkness falls.
As soon as it becomes completely dark, he hunts for a suitable place to
build a dam and soon finds a site to his liking. On one side of the
stream a thick clump of alders projects from the bank, and on the other
a water-soaked log is half buried in the bottom of the creek. From these
anchor points, he begins his dam, building toward the middle from each
side. The work calls for a great deal of the alder brush to be cut and
sunk in the bed of the stream. There it is weighted down with rocks and
mud until secure. Additional brush is brought and interwoven with the
first; gradually the structure grows until in a few days it converts the
stream into a quiet pool deep enough to hide the beaver, should an enemy
appear. As the water rises it covers the bases of the alders, which
begin to die in the pond.
The beaver next turns his attention to building a lodge. Selecting a
point to one side of the current entering the pond, he begins as he did
with the dam by sinking brush to the bottom and weighting it down with
rocks. As he builds, he cleverly fashions several underwater entrances
to the house that will be. When he has finished, the house projects
several feet above the water, and the materials are so thoroughly
interlaced and plastered that even the most determined enemy would
despair of gaining entry to the living room. Debris from the
construction has floated downstream to become lodged in and on the dam,
making it more secure and watertight that it was when first built.
With the dam and the lodge both completed, the next task is to collect a
food supply for the following winter. This is carried on intermittently
during the autumn. It consists of cutting down aspens, whose bark the
beaver dearly loves, sectioning the branches and small trunks into
pieces which may be handled conveniently, and dragging them to the pond.
Once in the water, they are weighted down and will remain in good
condition for a long time. The beaver is joined in this task by a female
which has also migrated from an overcrowded colony. Two need more food
than one, consequently their trails begin to head a little farther into
the aspen forest as they work through the crisp autumn nights. These
trails converge as they leave the forest and approach the pond, and end
in a few well-developed mud slides that enter the water. Constant
traffic of the wet beavers leaving the water keeps the slides moist and
slippery.
As winter settles in on the mountains, a thin skim of ice begins to form
on the edges of the quiet water on cold nights. Then one night it
freezes completely over. This causes the beavers no inconvenience at all
because if on one of their underwater excursions they should wish to
surface for air, they have but to swim to a shallow place with firm
bottom, and with one quick lift of their powerful muscles break a hole
through the ice with their backs. They can break surprisingly thick ice
in this way. The beavers live in comfort and plenty throughout the
winter. The living room of the lodge has been furnished with comfortable
beds of the cattails that have already become established along the edge
of the pond. The lodge, although tightly built, still admits enough air
for the beavers and food is stored in plenty on the bottom of the pond.
As the bark is gnawed from the aspen branches, the bare poles are added
to the bulk of the house or used in further construction of the dam.
Before long, the mild southwestern winter merges into spring.
In late spring the beaver family is considerably increased by the
arrival of four miniature beavers. They weigh but 1 pound each at birth
and are fully furred. At this time, the father is ostracized and the
mother and her young live together in the lodge. When the young are
about 3 weeks old, they take to the water for the first time. They
quickly learn the beaver method of swimming; this is to kick with the
hind feet and let the forelegs trail loosely alongside the breast, using
the flat tail both as elevator and rudder. The young beavers are called
kits, and indeed are as playful as true kittens can be. It is most
amazing to watch them cavorting about in the water with as much ease as
youngsters of other mammals do on dry land. As autumn nears, this play
is exchanged for the sterner duties of existence, and the young take
their places as adults of the family.
Fifty years pass. As the colony increases the dam must be made larger,
new lodges must be built; and when the trails to the aspen forest become
too long, canals are dug part way out to lessen the hazards which may
befall the beaver on dry land. The pond gradually silts up to higher and
higher levels until at last it is full of black, fertile soil. All of
the aspens within reach are finally cut down and the hungry beavers turn
to the resinous bark of the spruces. Finally the struggle is given up.
The beavers migrate to a new location, and the following spring a
freshet tears out the center of the dam. Now the pond is gone. With it
are gone the trout that played in its depths, and the teal that rested
there on their way south. In its place is a beaver meadow, a grassy park
in the center of the spruce forest with spring flowers spangling its
green surface. Aspens are already beginning to crowd in about its edges,
and the creek is cutting deeper into its soft soil with every spring.
Before long heavy erosion will begin to take its toll, and some day in
the future a male beaver will again come galloping awkwardly down the
slope.
The changing conditions which such a cycle bring about are almost
impossible to evaluate. At least three climax types of environment are
represented: those of the alder thicket, the beaver pond, and the beaver
meadow. In a graphic fashion this cycle illustrates what is going on in
Nature continually, more slowly perhaps, but just as surely.
Porcupine
_Erethizon dorsatum_ (Greek: to irritate in allusion to the quills and
Latin: pertaining to the back)
Range: Most of North America north of the Mexican border. Notable by
their exception are the south central and southeastern United States.
[Illustration: Habitat map]
Habitat: Usually associated with conifer forest, yet may sometimes be
found miles from any forest. An inhabitant of all life zones up to
timberline (Arctic-Alpine).
Description: A black to grizzled black and yellow creature covered with
quills. Total length 18 to 22 inches. Tail 7 to 9 inches. Weight 10 to
28 pounds. Body short and wide; supported by short bowed legs. Tail
heavy and muscular, armed with short slender quills. Head small with
dull eyes and long black whiskers, but with short ears. The incisors are
extremely large and are of a bright, rich yellow color. The quills are
shortest on the face and reach their greatest length near the middle of
the back. Often they are nearly hidden in the coarse, seal brown to
black underfur. The long guard hairs are also seal brown close to the
body, but change to a rather sere yellow at the tips. Only one young is
brought forth each year in a den among the rocks, or sometimes in a
hollow log. The young are among the most precocious of any mammal.
The porcupine in North America is considered as belonging to but the one
species _dorsatum_, although there are seven subspecies. The most common
subspecies found in the Southwest is _epixanthum_ (Greek _epi_, upon,
and _xanthus_, yellow), sometimes called “yellow-haired” porcupine. The
porcupine is unique among North American mammals in bearing the sharp
quills which are perhaps its most interesting feature. Certainly they
are responsible in large part for the unusual life history of this
misunderstood animal.
Quills are no more than greatly modified hairs, and in sorting through
the various types of pelage on a porcupine’s back, a few examples will
be found which are intermediate between the hair and the quills. This
does not mean that coarser hairs gradually turn to quills. Each follicle
produces hair or quill, as the case may be, for the life of the animal.
A quill consists of three well-defined parts: a solid sharp tip usually
black in color; a hollow shaft, which is white; and a root similar to
that of a hair.
[Illustration: porcupine]
The sharp tip is smooth for a fraction of an inch, but from this point
on, it is covered with a great number of closely appressed barbs. These
can be felt by rubbing the quill the “wrong” way bet
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