Mammals of the Southwest Mountains and Mesas

Part 2

Chapter 23,918 wordsPublic domain

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.

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.

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.

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.

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.

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.