Part 14

Probably no mammal in the United States is more certain soon to become extinct than these great bears. Many factors contribute toward this end, chief among them being the low reproduction rate and the rapid decrease of its range because of an increase in stock raising and agriculture. Ousted from its former haunts, the species is now found chiefly in only the few areas where it is rigidly protected. It seems extremely unlikely that it can long survive this reduction of its once unlimited range. This is the culmination of a program of destruction wrought on the grizzly since penetration of the white man into the West. It but follows the disappearance of other, less well known bears which lived in the Southwest at that time.

When the Mountain Men came into the West in the period from 1800 to 1850 they found a huge, light-colored bear roaming the foothills of the desert country. For want of a better name they called it the “gray bear.” From the accounts of that time it is now assumed that it was a grizzly; at any rate, it was said to have been extremely ferocious, a trait which led to its downfall. In the space of about 70 years this animal was discovered, hunted and exterminated, all without a specimen of any kind being preserved. Today not a trace of this big predator remains. Its fate illustrates the usual result of contact between a dangerous, highly specialized animal and man. The question which arises is, should any group of men ever be allowed such control over a wilderness that they are able to exterminate the fauna and flora to the detriment of succeeding generations? The answer seems obvious if we consider that “we but hold these things in trust.”

Many species of the grizzly are recognized by taxonomists, but few are alive today. In the United States only New Mexico, Colorado, Utah, Wyoming, Montana, and Idaho still have some of these big animals. In some other western States they have but recently become extinct. California is thought to have lost its last grizzly in 1925. The few survivors are probably all of the species _horribilis_. Since grizzly country is also black bear country, the layman may become confused in identifying the two species. A few important differences make identification easy.

The first and most conspicuous field mark is the prominent shoulder hump of the grizzly. The male black bear will sometimes with age develop a shoulder hump, but it cannot compare with that of the grizzly. Second, the grizzly has what has been described as a “dish” face; that is, a concavity in the general shape of the front of the face, whereas the black bear develops a definite “Roman” nose. Third, the claws of the grizzly are twice as long as those of the black bear; this is most noticeable in the tracks. If one is close enough to see this characteristic in the field, he probably is too close for safety! Lastly, the attitude of the two species toward each other when they meet on common ground is characteristic. As a rule, the approach of a grizzly to a garbage dump is enough to put all black bears to flight. There is no intermingling of the two species; the grizzly is the master and the black bear will not challenge his authority.

In most of its habits the grizzly resembles the black bear. It is omnivorous to the same degree, but somewhat more predatory. It also goes into hibernation for the winter, and the cubs are born during this inactive period. They receive the same rigorous training as that accorded their black cousins, and like them, are able to climb into the trees and out of harm’s way. As they grow older, this ability leaves them with the growing of the long claws, and adult grizzlies are supposed to be unable to climb. In one respect the grizzly differs from not only the black bear but from most other native mammals. It has never learned to fear man to the same degree that other creatures have.

Whether the grizzly’s belligerent attitude stems from fear or contempt is a moot question. The important point to remember is that a grizzly should be avoided at all times. Injuries suffered by humans in their contacts with black bears are usually accidental rather than the result of deliberate assault by the animal. Grizzlies have been known to charge without other provocation than trespass on what they consider their territory. Surely the public can afford to humor this irascible giant. A little consideration for its irritable nature is not too great a price to pay for its continued existence in our rapidly dwindling numbers of large carnivores.

Vagrant shrew _Sorex vagrans_ (Latin: a shrew ... wandering)

Range: Confined to mountains of western United States and Canada, and northern and southern Mexico.

Habitat: Moist places in forests of the Transition Life Zones and higher.

Description: A tiny creature with a long nose. Total length 4 to 5 inches. Tail 1½ to 2 inches. Color reddish brown to black above with sides drab and lightening to gray below. Tail indistinctly bi-color except for the last half which is dark all the way around. Head round and narrowing to a long, pointed, somewhat flexible nose. Long whiskers are found along the sides of the upper jaw. Eyes and ears so small as to be difficult to see. Little is known of breeding habits of the shrews. The vagrant shrew is said to breed at any time of year and to have from 5 to 11 young in a litter.

Shrews are the smallest American mammals. Their size and secretive habits combine to make them among the least known of native animals. They are classed as insectivores, although they eat other small mammals as well as insects. They may be distinguished from mice by their bicuspid incisors and modified canine teeth. Another difference is that shrews have five toes, in contrast to the four-toed feet of mice.

As far as is known at present, certain species of shrews are the only poisonous mammals. The big short-tailed shrew (eastern United States) has a toxic substance in its saliva which helps subdue some of the animals it captures. It is thought that some western species also have this peculiarity. Though shrews are among the tiniest animals known, they are not unduly persecuted by larger predators. This is thought to be partly because of certain glands on the shrew’s body which give it an offensive odor.

An outstanding characteristic of shrews is their need for a constant supply of food. Because all small animals lose heat quickly, they must eat almost constantly to replace this loss. Some species will eat their own weight in food as often as every 3 hours. An outstanding exception is the water shrew, which can do without food for as long as 2 days without starving to death. Since most shrews live in or near the water, they find ample food in the insects, spiders, minnows, and small mammals which live in moist locations. The group is as ferocious as it is voracious. Most shrews do not hesitate to attack animals outweighing them several times. It has been said that if shrews were as big as squirrels they probably would even attack man.

In the mountains of Utah, Colorado, and northern New Mexico the northern water shrew (_Sorex palustris_) may be encountered. It is somewhat larger than the vagrant shrew and will not be seen away from water. Gray below and black above, it is wonderfully camouflaged, whether in water or on land. It, like other shrews, has long whiskers known as vibrissae. Land shrews use these whiskers as tactile organs to help them follow the dark maze of their runways. Water shrews are thought to use them as sense organs in place of eyes to pursue the minnows, tadpoles, and water bugs they eat. Actually, the water shrew resembles a large water bug as it darts about below the surface surrounded by the silvery bubbles of air imprisoned in its fine fur.

Bats Order _Chiroptera_ (Latin: chir, hand, and optera, wing)

The special treatment accorded bats in this book is not given them by choice. It results from an inability to so clearly describe any one or two species chosen that the layman might be able to distinguish these from their numerous and equally interesting relatives. When one considers that numerically bats are thought to compare favorably with birds, that there are a great number of species divided into many genera, and that the four-State area with which we are concerned is invaded, so to speak, by eastern, northern, western and Mexican species besides having several of its own, it soon becomes apparent that this group can be described here only in the most general way. If some of the popular superstitions about bats are contradicted here, it is to be hoped the reader will find the facts no less interesting.

The adaptation for which bats are best known is their ability to fly. This specialized talent is shared by no other type of mammal. It is made possible by considerable modification of several structures of the body, that of the forelimbs being the most extreme. The bones of both the upper and lower forelegs are considerably lengthened, but cannot compare with the extreme elongation of the digits. The clawlike protuberance from the front of the wing corresponds to the thumb. The wing membrane stretched across the “fingers” is attached to the side of the body and to the hindlegs as far as the ankle. Most bats have another wing membrane, called the interfemoral membrane, which joins both hind legs, and in many species it also embraces the tail. The wing membranes look and feel somewhat like thin leather. Running through them is an intricate system of blood vessels. These not only supply nourishment to the membrane but also act as a radiator in cooling the blood stream during the strenuous physical labor involved in flight. The principles of flight are similar to those used by birds; that is, the wings are partially folded on the upstroke and fully extended during the down beat. This maneuver produces a rustling sound that is clearly audible in the quiet of a cave. In fact, if thousands of bats are disturbed at the same time it becomes a low roar.

The fact that bats are nocturnal, and at the same time lead an aerial life which necessitates flying through labyrinths plunged in total darkness, has been the cause of much research as to the means by which they can do this. It is now definitely known that they depend on a sonar system where, by emitting shrill cries, they are guided by the echoes rebounding from nearby objects. These “squeaks” range within a frequency of from 25,000 to 75,000 vibrations per second, which is too high for the human ear to register. The sounds are uttered at rates from about 10 per second when the bat is at rest to as many as 60 per second when it is in flight and surrounded by the many obstacles to be found in a cave. Fantastic as this performance seems, it is matched by a theory that tiny muscles close the bat’s ears to each squeak and open them again to hear only the echo.

The response of their vocal and hearing structure to this specialized use is truly amazing. There are no more unique faces in the mammal kingdom than those of the bats. Most bats have enormous ears with ridged and channeled interiors that probably have much to do with amplifying faint sounds. Set in front of the ear is a narrow, upright protuberance known as the tragus. Farther down the face, in the region of the nose, are other strangely shaped skin structures including the “nose leaf.” As yet the functions of these appendages are not entirely known, but it is suspected that at least part of their purpose is to beam the squeaks along a definite line and thus help orient the bat with its surroundings. With such an efficient system to guide it, the bat has small need for eyes. The expression “blind as a bat” is misleading, however, because most bats, in spite of their relatively small eyes, can see rather well.

Since most southwestern bats are insectivorous, with the exception of a very few species along the Mexican border which are considered fruit eaters, the question arises as to how they exist during the winter months when insects are not to be found. There are two common methods by which animals avoid such a lean period: by migration and by hibernation. Bats employ both. Some species are thought to fly as far south as Central America. Others group together in caves and hang in a deep torpor all winter. In this state of inactivity their body temperatures may fall to within one degree of their surroundings, and their rate of metabolism sometimes falls to one-eighteenth of that during active periods. As a rule, bats prefer a cool place for hibernation, because the cooler the temperature the slower the rate of metabolism. Body temperatures as low as 33.5° F. have been recorded in hibernating bats. The temperature must not fall below freezing, or the animals will perish. During this period of inactivity bats have been known to lose up to one-third of their weight.

Because of their secretive habits and nocturnal periods of activity, bats have few enemies other than man that are capable of making any serious inroads on their numbers. Consequently the birth rate is quite low in most species. Many have no more than one young each year; and the red bat, which bears up to four young, seems to be the most prolific in the United States. There is great variety in the methods by which different species care for the young. Some mothers leave the babies hanging to the roof of the cave while they go on their nightly search for food; others carry the young clinging tightly to their fur. The young mature quickly. They are usually able to fly within a month after they are born.

Despite much recent scientific study, bats are still among our least known creatures. Their insectivorous diet surely makes them of great importance to man. Beyond this, their immense numbers indicate that ecologically they must have tremendous influence on any area in which they live.

REFERENCES

Bailey, Vernon 1931. _Mammals of New Mexico._ North American Fauna, No. 53, Washington, D. C., U. S. Department of Agriculture, Bureau of Biological Survey.

Barnes, Claude T. 1927. _Utah Mammals._ Salt Lake City, The University of Utah.

Burt, William Henry and Grossenheider, Richard Philip 1952. _A Field Guide to the Mammals._ Boston. Houghton Mifflin Co., The Riverside Press, Cambridge.

Hall, Raymond E. 1946. _Mammals of Nevada._ Berkeley. University of California Press.

Ingles, Lloyd Glenn 1954. _Mammals of California and its Coastal Waters._ Stanford University Press. Stanford, California.

Jaeger, Edmund C. 1950. _Our Desert Neighbors._ Stanford University Press. Stanford, California.

Mearns, Edgar Alexander 1907. _Mammals of the Mexican Boundary of the United States._ Part 1. Washington D. C.: Government Printing Office.

Miller, Gerrit S. and Kellogg, Remington 1955. _List of North American Recent Mammals._ Washington: United States National Museum, Bulletin 205.

Nelson, E. W. 1918. _Wild Animals of North America._ National Geographic Society.

Warren, Edward Royal 1910. _The Mammals of Colorado._ New York: G. P. Putnam’s Sons.

Cockrum, E. Lendell 1960. _The Recent Mammals of Arizona._ Tucson: University of Arizona Press.

INDEX

A Abert’s squirrel. _See_ Tassel-eared squirrel. Alpine Life Zone, xiv Antelope. _See_ Pronghorn. _Antilocapra americana_, 4 Arizona gray squirrel, 36 Artiodactyla, 1

B Bats, 121 Bear, black, 112 grizzly, 117 Beaver, 67 Bighorn, 2 Bison, 8 _Bison bison_, 8 Black bear, 112 Black-tailed deer, 11 Bobcat, 85 Buffalo. _See_ Bison. Bushy-tailed woodrat, 60

C Canadian Life Zone, xiii _Canis latrans_, 92 _lupus_, 89 Carnivores, 79 _Castor canadensis_, 67 Catamount. _See_ Mountain lion. _Cervus canadensis_, 16 Chickaree. _See_ Spruce squirrel. Chipmunks, western, 44 cliff, 45 Colorado, 44 gray-necked, 44 least, 45 Uinta, 44 Chiroptera, 79, 121 _Citellus lateralis_, 48 Classification of animals, xv Cliff chipmunk, 45 Colorado chipmunk, 44 Cottontail, mountain, 26 Cougar. _See_ Mountain lion. Coyote, 92 _Cynomys gunnisoni_, 51 _leucurus_, 51 _parvidens_, 51

D Deer black-tailed, 11 mule, 10 fantail, Sonora, 11, 14 white-tailed, 13 Deermouse, 57 Douglas squirrel. _See_ Spruce squirrel.

E Elk, 16 _Erethizon dorsatum_, 72 Ermine. _See_ Short-tailed weasel. _Euarctos americanus_, 112 _Eutamias cinereicollis_, 44 _dorsalis_, 45 _minimus_, 45 _quadrivittatus_, 44

F _Felis concolor_, 80 Field mouse. _See_ Mountain vole. Fox, red, 87

G _Glaucomys sabrinus_, 42 Golden-mantled ground squirrel, 48 Gopher, northern pocket, 75 Gray-necked chipmunk, 44 Gray wolf, 89 Grizzly bear, 117 Ground squirrel, golden-mantled, 48 _Gulo luscus_, 95

H Hare, snowshoe, 22 Hoofed animals, 1

I Insectivores, 79

J Jackrabbit, white-tailed, 24

K Kaibab squirrel, 34

L Lagomorphs, 21 hare, snowshoe, 22 jackrabbit, white-tailed, 24 cottontail, mountain, 26 pika, 28 Least chipmunk, 45 _Lepus americanus_, 22 _townsendi_, 24 Life zones, xiii Alpine, xiv Canadian, xiii Lower Sonoran, xiii Transition, xiii Upper Sonoran, xiii Lion, mountain, 80 Long-tailed weasel, 106 Lower Sonoran Life Zone, xiii _Lutra canadensis_, 101 Lynx, 85 _Lynx canadensis_, 86 _rufus_, 85

M Marmot, yellow-bellied, 53 _Marmota flaviventris_, 53 Marten, 97 _Martes americana_, 97 Meadow mouse. _See_ Mountain vole. _Mephitis mephitis_, 110 _Microtus montanus_, 58 Mink, 103 Mountain cottontail, 26 Mountain sheep. _See_ Bighorn. Mountain lion, 80 Mountain vole, 58 Mouse, western jumping, 59 white-footed. _See_ Deermouse. Field. _See_ Mountain vole. Meadow. _See_ Mountain vole. Mule deer, 10 Muskrat, 64 _Mustela erminea_, 105 _frenata_, 106 _rixosa_, 106 _vison_, 103

N _Neotoma cinerea_, 60 Northern flying squirrel, 42 Northern pocket gopher, 75

O _Ochotona princeps_, 28 _Odocoileus couesi_, 14 _hemionus_, 10 _virginianus_, 13 _Ondatra zibethicus_, 64 Otter, river, 101 _Ovis canadensis_, 2

P Pack rat. _See_ Bushy-tailed woodrat. Painter. _See_ Mountain lion. Panther. _See_ Mountain lion. _Peromyscus maniculatus_, 57 Pika, 28 Pine squirrel, 39 Porcupine, 72 Prairie dog, white-tailed, 51 Pronghorn, 4 Puma. _See_ Mountain lion.

R Red fox, 87 Red squirrels. _See_ Spruce squirrel. River otter, 101 Rodents, 21 _Sciurus aberti_, 31 _arizonensis_, 36 _kaibabensis_, 34

S Short-tailed weasel, 105 Shrew, vagrant, 119 Skunk, spotted, 108 striped, 110 Snowshoe hare, 22 Sonora fantail deer, 11, 14 _Sorex vagrans_, 119 _Spilogale gracilis_, 108 Spruce squirrel, 39 Squirrel, Abert’s. _See_ Tassel-eared squirrel. Arizona gray, 36 chickaree. _See_ Spruce squirrel. Douglas. _See_ Spruce squirrel. golden-mantled ground, 48 Kaibab, 34 flying, northern, 42 pine, 39 red. _See_ Spruce squirrel. spruce, 39 tassel-eared, 31 _Sylvilagus nuttalli_, 26

T _Tamiasciurus hudsonicus_, 39 Tassel-eared squirrel, 31 _Thomomys talpoides_, 75 Trade rat. _See_ Bushy-tailed woodrat. Transition Life Zone, xiii

U Uinta chipmunk, 44 Upper Sonoran Life Zone, xiii _Ursus horribilis_, 117

V Vagrant shrew, 119 Vole, mountain, 58 _Vulpes fulva_, 87

W Wapiti. _See_ Elk. Weasel, least, 106 long-tailed, 106 short-tailed, 105 Western jumping mouse, 59 White-footed mouse, 57 White-tailed deer, 13 White-tailed jackrabbit, 24 White-tailed prairie dog, 51 Wolf, gray, 89 Wolverine, 95 Woodchuck. _See_ Yellow-bellied marmot. Woodrat, bushy-tailed, 60

Y Yellow-bellied marmot, 53

Z _Zapus princeps_, 59

Transcriber’s Notes

—Silently corrected several palpable typographical errors.

—Retained publication information from the original source.

—In the text versions, included italicized text in _underscores_.