MAMMALS
of the southwest
MOUNTAINS
and
MESAS

by
GEORGE OLIN
illustrations by
EDWARD BIERLY

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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)

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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)

spruce squirrel

Range: Utah, Colorado, Arizona and New Mexico in the Hudsonian and Canadian Life Zones.

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.

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.

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)

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.

Colorado

Uinta chipmunk

Uinta

2. Gray-necked chipmunk (Eutamias cinereicollis)

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.

Gray-necked, Cliff

3. Least chipmunk (Eutamias minimus)

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.

Least

4. Cliff chipmunk (Eutamias dorsalis)

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.

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.