Animal Life in the Yosemite
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MULE DEER. Odocoileus hemionus hemionus (Rafinesque)

Field characters.—Size large, mature individuals standing 32 to 42 inches high at shoulder. Males more than one year old bear short spike-like antlers; in later years antlers more or less branched. Ears very large, 8 to 9 inches tall from base to tip, 4 inches across at greatest width. (See pl. 39b). Tail narrowed near base, black on outer surface, white on under side. Adults, bright reddish brown in summer, grayish brown in winter; rump and throat whitish; young fawns reddish brown, spotted with white. Footprints small for size of animal, sheep-like, but sharply pointed (pl. 40d). Droppings elliptical, 1/2 inch long or less, black.

Occurrence.—More or less common, according to season and altitude, almost through out the Yosemite region; recorded from hills west of Pleasant Valley eastward across the mountains to Mono Craters. Summer range chiefly between altitudes of 3500 and 8500 feet; winter range, below level of deep snow, that is, mostly below 5500 feet. Prefers chaparral country. Seen singly or in small bands.

In the days of '49, when white men first thronged the Sierran foothills, no less than four species of horned or antlered big game animals inhabited the Yosemite region. At the eastern border of the San Joaquin Valley was the Dwarf or Tule Elk; on the plains of the San Joaquin and in Mono Valley was the American Antelope; on the highest parts of the Sierra Nevada was the Sierra Mountain Sheep; and in the intervening middle altitudes was the Mule Deer. Now all save the last have vanished, probably never to return; but the Mule Deer is still present over most of its early range, though doubtless in but a fraction of its original numbers.

Mule Deer are most frequently seen by foot travelers in the summer on and near the trails above the rim of Yosemite Valley, but autoists en route to or from the Valley, especially during the fall months, often see them along the roadsides. The deer range over practically all of the hilly and mountainous country in the Yosemite region, from the westernmost extension of the brush belt bordering the San Joaquin Valley east over the crest of the Sierra Nevada to Mono Valley. They are not uniformly distributed over the whole area, however, nor do they occur in all portions of it at all times of the year. A small number remain in the Upper Sonoran chaparral belt of the western foothills during the summer season, and a few also occur on the east base of the Sierras, but the great majority of the animals are to be found at this time in the brush country of the higher mountains, in the Transition and Canadian life zones, at altitudes of from 3500 to 8500 feet. Some wander up toward timber line, our highest record being 10,600 feet, near Fletcher Lake. In winter they descend to lower altitudes, there being thus a distinct migratory movement twice each year. Those on the western side of the mountains migrate to the region from Bridal Veil Meadow (3900 feet) and the southern slope of Pilot Peak (at 4500 feet) west to Forty-nine Gap (1500 feet), while the animals on the east slope cross Mono Valley to the country east of Mono Craters. Individuals occasionally range on the west as low as Snelling, in the Merced River bottom well beyond the westernmost foothills.

The two factors controlling the local distribution of deer in the Yosemite region are the presence of the right kind of brush for food and shelter, and the absence of deep snow. Deer depend chiefly on certain brush plants for their sustenance. When these shrubs are covered with snow, or surrounded by snow more than 18 inches deep, the animals are unable to feed. Their altitudinal migrations seem to be controlled entirely by snowfall; they ordinarily remain in the high mountains in the fall until the first snow of the season sends them downhill and concentrates them along the western boundary of the Park. As a rule, they do not stay where the snow lies to a depth of more than 1-1/2 feet, but, other conditions permitting, they do remain just below this level. Their numbers in the most favorable localities may tend to become larger than the supply of forage will support, and then competition forces many of them still lower down, into the foothill chaparral belt entirely west of the Park boundary. The migrant deer go farther westward than do those animals which reside throughout the year in the foothills. Large numbers of deer from the northern part of the Park winter on the sunny, snow-free, south-facing slopes of Rancheria and North mountains in the Tuolumne drainage; while those from farther south range over the slopes within ten miles west of Chinquapin, on the Merced watershed.

Park rangers see more deer in the early and late winter months than during the midwinter or midsummer seasons. This is, in part, because of the fact that in the former periods the animals are on the move, leaving the tracts of heavy brush, and often using the roads or trails. For example, 261 deer were seen in November, 1915, 43 being noted in a single day near Chinquapin. In December of the same year 396 were observed, 37 being seen by one ranger in a single day. But in January, 1916, only 8 deer were seen; storms and deep snow had driven them far to the westward. In March, 1916, 318 deer were noted by the rangers, 60 being seen in one day at Wawona. During the period of heavy snow referred to above, residents of El Portal reported seeing a band of 60 to 70 deer in the hills a few miles south of that place.

If the first storm is a heavy one the deer leave the altitudes with a rush. Mr. C. C. Bull has told us that in Hetch Hetchy Valley after a big storm so many deer have passed a certain point in single file as to leave a beaten trail in the 10 or 12 inches of snow which lay on the ground. If the winter is a light one, with alternate periods of clear and stormy weather, the deer move back and forth, going up as the snow recedes and descending again when a fresh fall occurs. The deer which summer on the east slope of the Sierras, in migrating to the mountains east of Mono Craters either pass along the slopes of the Craters or else go directly across the open plains just south of Mono Lake. According to our experience in 1914-1916, deer are not commonly observed on the floor of Yosemite Valley in summer, though several does and their fawns may appear there in August; by October, and throughout the winter, a good many frequent the lower end of the Valley. In later years, 1919-1920, more have been seen throughout the summer in the Valley, even bucks.

The relative deer populations of the foothills and high mountains during the summer were probably originally determined by food supply—as many as could be supported throughout the year by the forage and shelter of the foothill country remained there, while the balance were led to seek the higher altitudes for the summer season. Habits so developed in the deer of the two different belts have persisted even in the reduced populations of the present day. There is, indeed, some evidence that slight differences in size and structural features exist on an average between the deer resident in the foothill belt (Upper Sonoran Zone) and those which seek in summer the higher altitudes.

The Mule Deer which inhabit the Yosemite National Park seem to have responded favorably to the protection afforded them; they are remarkably tame, and will usually permit a person who moves slowly to approach very near. Despite their size, their somber coloration renders them surprisingly inconspicuous when in brush thickets, but the recurrent flapping of their big mule-like ears sometimes betrays their presence. They exhibit great curiosity and often when frightened out of a trail will circle about the traveler and may soon be discovered gazing at him from some new position. The following excerpt from the notebook of the senior author describes an interesting meeting with some of these animals.

Ridge between Yosemite and Indian creeks, June 4, 1915. Four deer, an old doe and three smaller deer without evident horns, were walking about 50 feet from me. I first came upon them suddenly; the three smaller ones stampeded over a rise of ground; but the old doe was curious and even came toward me. I remained quiet, only wiggling my fingers, and this interested her. The three young had vanished. Presently she began to look back at intervals, and they finally appeared again. She evidently wished to follow up the ridge, so she walked in a half-circle around me, the other three following at a little distance, single file. . . . They all disappeared over the ridge a few minutes ago, but at this moment three of them are staring at me over a log 60 yards off. The female has a (bullet?) hole through her left ear. I can see daylight through it. The others are about two-thirds the size of the female; probably last year's fawns (could she have had three?). . . . The doe has just now become excited and uttered 8 rather loud snorts in irregular succession, schfew, and has given several stiff-legged bounds over the ridge. The young ones have vanished. They all did a great deal of flapping of their big ears, as if the flies bothered them.

On June 24, 1920, about 9 A.M., a company of 5 deer were come upon in a grove of close-growing yellow pines on the floor of Yosemite Valley near Clarke Bridge. They were all males, but no two were of the same size. The antlers, in the velvet with knobby ends, varied from short 'spikes' less than half the height of the ear to the big three-forked type. These deer, the largest one in the lead, moved along slowly, paying little attention to the human observers only 40 yards or so off. They kept reaching up to nip off the highest sprays of ceanothus, which here was shade-grown and sparse of leafage.

Trainmen on the Yosemite Valley Railroad told us that deer are frequently encountered on the tracks at night. The animals seem dazed by the glare of the headlight. The enginemen always slow up so as to give the animals a chance to 'come to' and get off the track.

Mule Deer are browsing rather than grazing animals; that is to say, they prefer leaves and young shoots of certain shrubs and trees to grasses and other terrestrial plants. At all times and in all altitudes their preferred forage is deer brush, mountain lilac, snow bush, and other representatives of the plant genus Ceanothus. Among all of these, Ceanothus integerrinus, the big-leaved, sweet-flowered bush of middle altitudes, is the favorite. When several other shrubs such as manzanitas and scrub oaks are available, ceanothus will be the only one showing bite marks. A deer nips at the foliage with a diagonal movement of the head and neck, and leaves the bark of the twig ends raveled out instead of cut off evenly. Deer are known to eat the bark of the incense cedar, particularly from young trees, and occasionally leaves of the black oak. In spring they nibble young shoots of dogwood along streams where they come down to drink. When the supply of acorns or chinquapin burrs is large, the deer feed on them with evident relish. At times, as when browse is scant or of poor quality, the deer feed on grass. This is notably true in the semi-barren Hudsonian Zone, where brush of any sort is almost wanting. They may also take willow leaves there. A buck seen at Forty-nine Gap, in the lower foothills, in December, 1915, was feeding on grass, even though several kinds of brush plants were available nearby; but this was an exceptional instance.

The deer of this region have profited, to some extent, through civilization. At the Chinquapin barns they frequently pick up hay which has been scattered when bales are being unloaded, and the men employed there and at Eight-mile have attracted and tamed the deer by putting out salt for them. Deer also visit the salt licks established by cattle men for their stock both inside and outside the western boundary of the Park. Hunters, however, take advantage of this habit and often lie in wait for the animals at these artificial licks. Finally, deer have been seen consuming the remains of lunches. A doe seen near a garbage can above Yosemite Falls one afternoon in late June, 1915, was munching a discarded sandwich with evident satisfaction.

Deer may be seen moving about at any hour of the day or night, but they are active chiefly during the late afternoon and early evening hours. Then the brush is free from dew and presumably more relished by them. On moonlight nights they have been seen foraging on the scanty growth of grass to be found on the forest floor; and they are often heard running at night. They are least active during the heat of the day. Then they are lying down, in their 'beds,' resting and sleeping.

A deer bed is nothing more than a slight depression in the surface of the ground, 2 to 3 feet in diameter, sometimes scraped free of such surface litter as pine needles. It is usually placed in the shade on a sidehill some distance below the top of a ridge, from which the animal can have unrestricted view for a considerable distance. The situation most favored is a small clearing in the brush, sheltered by some small coniferous tree. Certain warm, south-facing slopes near the crests of the higher ridges are much frequented for resting places by large bucks. Park rangers term these animals "granite bucks" and say that they are unusually large individuals and that they are able to winter at higher altitudes than do the other deer.

Aside from actual sight of the animals, the presence of 'sign' (characteristic droppings and footprints) is, of course, dependable evidence of the presence of deer in a region. Footprints of deer are much smaller than those of cattle and more pointed than those of either calves or sheep. The largest hoof mark which any of our party saw was that of an old buck. It measured 2 by 2-3/4 inches. In general the tracks of does (pl. 40d) are smaller and more acutely tipped than those of bucks, but, in examining many individual tracks, it has proved impossible to say whether they were made by a buck or by a doe. In late summer the river-side sand bars in the vicinity of Merced Lake are in some places literally plowed up by the little tracks of fawns which have been led down there by their mothers to drink.

Deer take more notice of noise than of motion. If the observer moves quietly and slowly the deer usually will not become frightened, but should a twig be broken under foot or any other sharp noise be made, they are apt to be off at once. The relatively large size of their ears (pl. 39b) probably means that, as a rule, they depend on hearing rather than on sight for the detection of enemies.

When frightened or excited, Mule Deer utter a sharp snort, and when running away often 'flash' the tail and rump so as to form a white 'flag' against the darker color of the rest of the body, reminding one of the appearance of a cottontail rabbit. Possibly this is a warning sign, to other deer, of the proximity of danger, or a signal for fawns to flee. When, however, two or more deer are alarmed and retreat from the vicinity of the observer, they usually separate and go in different directions, reuniting when they again feel safe. This is commonly true of does with young fawns, although sometimes the fawns accompany their mothers closely in a retreat.

By passing back and forth over a preferred route through the brush or forest, deer often make distinct trails. These are easily distinguished from horse or cow trails by the facts that they are narrower and do not continue for any great distance in a given direction; they end as soon as a good browsing area is reached. Deer do not follow man-made trails consistently but often take short-cuts. On the zigzags between Ilillouette Creek and Glacier Point we have seen both deer and bear tracks in abundance. The bears had plodded along, following every twist and turn, while the deer had taken short-cuts up or down steep slopes.

The summer coat of the Mule Deer, which is worn from about June until October, is of a reddish brown color and the hairs are sparse, short, and straight. The winter coat, which is worn during the remaining portion of the year, is much darker, being grayish brown ("blue," in the hunter's language), and composed of longer, much more numerous, and slightly crinkled hairs. The greater number and length of the hairs and their irregular form are probably for the purpose of furnishing a greater number of discontinuous air spaces in the coat, which help to keep the animals warm during the cold of winter.

The ground color of the coat of a newborn fawn is reddish brown heavily marked with large (1/2 inch) white spots. The original brilliant contrast of this pattern persists only a short time, as the spots soon become dulled and finally disappear. Such evidence as we have indicates that this change is accomplished by wear and also by the appearance of numerous long reddish hairs. Thus by mid-August the fawn is reddish brown, similar in color to the summer coat of its parents. This in turn gives way in October to the regular gray winter coat. The hair of all these pelages is much softer, and in the first winter coat less crinkled, than is that of the adults.

Mule Deer have three gaits, all of them stiff-legged. When foraging or moving quietly along they walk with a peculiarly individual movement of the legs, each foot being lifted and set vertically down. This, combined with the very small size of the hoofs, results in a surprisingly quiet tread. In fact we are led to the belief that the smallness of the hoof is an adaptation in the direction of quiet movement. The second gait is a stiff-legged trot, in which the feet move alternately; and the third is a gallop, or "peg-legged lope," in which the fore and hind feet move in pairs simultaneously. This last is the gait which is used when the animals are beating a hurried retreat after being thoroughly frightened, and the speed which they make over short distances is surprising. This bounding gait serves two further purposes—to permit the animal to clear the brush in which it characteristically lives, and, with each upward leap of the animal, to enable it to see above the brush and thus to extend considerably its field of vision. Does, especially when carrying young, are said to lope with an easier carriage of the body than the bucks.

Every adult male deer normally possesses antlers and these are used for display and combat during the mating season. These are solid bony structures borne on the skull, grown and shed each year, and entirely different in form and origin from the permanent 'hollow' horns of cattle and sheep. The antlers begin to grow out in early spring and when first in evidence are nothing more than short knobs on top of the head between and a little above the eyes. While growing they are covered with a thick densely haired skin called 'velvet,' and this skin is richly supplied with blood vessels which serve to bring the materials necessary for growth. While growing, the antlers are very sensitive to touch and the deer are then notably careful of them; usually they forage in the open where there is less danger of coming in contact with limbs of trees or with other objects. The development of the antlers is rapid; by late May or mid-June they are one-third to one-half longer than the ears though still blunt-ended; by August their growth is complete, and they have become sharp-pointed. The blood supply ceases, the velvet dries, and the deer gets rid of it by rubbing the antlers against trees and shrubs. At this season bucks are often seen with pieces of dried velvet dangling loosely from their antlers. The bucks retain their antlers through the autumnal mating season and until early winter, when they shed them. A buck seen by Mr. C. C. Bull on March 16, 1916, was still carrying its antlers; but this was exceptionally late.

The number of 'points' or 'tines' on each one of a pair of antlers is commonly thought to be an index to the age of the animal bearing them. Yearling males with simple, unbranched antlers are called 'spike bucks,' while older animals are termed 'two-point bucks,' 'three-point bucks,' and so on, according as each of their antlers bears two, three, or more tines. Very old bucks are said not to have the number of points their years would prescribe. The largest number of points seen by us on any deer in the Yosemite region was six, but Lawrence Souvelewsky reported seeing a seven-point buck in the vicinity of Merced Lake.

The mating or rutting season occurs chiefly in October. Very little is known about the mating habits of the Mule Deer save that the animals are then very wary. Two does seen in Ten Lakes basin on October 10, and a buck and a doe at Aspen Valley on October 15, were all very wild. By November this wildness has passed and the animals may again be closely approached. Soon after this the bucks shed their antlers.

The fawns are born about the first of July, but the does keep their charges hidden in the brush for a month or more before permitting them to forage in the open. In 1915 the first one was seen on July 27, and by early August fawns were observed almost daily. Two constitute the usual number although sometimes there is only one and occasionally there are three. By the time they are seen regularly with their mothers the young animals are about one-fourth to one-third grown, and pretty well able to take care of themselves. The fawns run with their mothers through the first year. Early in June we saw many groups comprising a doe and 1, 2, or 3 fawns which were about two-thirds grown. By the latter part of the same month the does desert these yearlings in anticipation of the arrival of the next litter. It is a common belief, substantiated by known facts, that fawns which are born at low altitudes remain there throughout their lives, while those born in the mountains migrate up and down every season.

Coyotes, especially the big Mountain Coyotes, occasionally 'pull down' fawns or sickly adults. If caught in snow more than 18 inches deep, even adult and able-bodied deer are apt to be run down by these predators. The coyotes run easily on the top crust of the snow, but the deer break through and flounder helplessly in the deeper drifts. In the Yosemite region, however, the chief wild enemy of the Mule Deer is the Mountain Lion. The way in which lions capture deer is described in another chapter (p. 97), where also the numbers probably killed each year are estimated.

The interrelation of Mountain Lion and Deer has naturally become an important subject of discussion and concern among sportsmen, to whom a deer is something to be sought after, both for its flesh and as a trophy. In a very definite sense the Mountain Lion is, in territory open for hunting, the sportsman's rival; hence, from the sportsman's standpoint, the lion should be eliminated. But in the Yosemite National Park, where the aim is to preserve free from human interference all the animal life, it is the hunter who is eliminated, and so the situation is altogether different.

The close grazing of cattle in the territory to the west of the Park, which is comprised in the wintering grounds of a good proportion of the Yosemite deer population, has inevitably reduced, especially in hard years, the number of deer which can be carried over there through the winter. Not only the grasses, but most especially certain thin-leafed kinds of deer brush, have been browsed down by cattle and goats to mere vestiges of their former quantity; and the deer are hard put to it when the snow lies far down on the west Sierran slopes. In last analysis, counting out man, the important factor in the reduction of the numbers of deer is the reduction in the quantity of food available to them at the most critical time of the year, rather than the levy upon their numbers by lions.

Except as the factor of hunting and poaching in the territory along the western edge of the Park also affects the deer population of the Yosemite, we do not see that the permanent existence, in relatively normal numbers, of Mountain Lions within the area in question can be expected to reduce the total population of the deer which will be maintained from year to year. In other words, if the Yosemite Park is administered as a true 'refuge' for its animal as well as its plant life, then primitive conditions should be maintained absolutely, to the end that all the constituent species persist in the same relative numbers as they did in early times. The maximum numbers of any and all herbivores which can exist will be determined by the amount of plant food available at the season of least supply; and the numbers of carnivores which can exist will be determined by the amount of animal food available to them at the season of scantiest supply.

Occasional purely fortuitous accidents happen to deer. One of the Park rangers found a deer held fast by one of its forefeet in the crotch of a young black oak. The animal had twisted its leg nearly off in its attempt to free itself.

Within the boundaries of the Yosemite National Park the Mule Deer receive every possible protection. The rangers are careful of the interests of the deer and little if any poaching takes place. But in the area lying immediately to the west little regard seems to be paid to the game laws. Some residents of this region believe that they have a vested right to kill deer "whenever and wherever they please." When confronted with the statement that there is a State law protecting the animals, they ask, "Can you blame a man for going after a deer [despite the law] when meat is scarce?" To this we answer, "We most certainly do." The doctrine that our wild game belongs to all the people (to be conserved in the interests of all) and not just to those residing in the immediate vicinity seems not to have reached them as yet. A resident of El Portal openly boasted to one of our field party that he had been on a deer hunt during the first week in December, nearly two months after the close of the legal season for killing deer.

Certain residents stated that deer are not now more than 50 per cent as numerous as in earlier years. When pressed for the reasons why deer have decreased the replies were:

1. The deer have moved back.

2. Mountain Lions and other "varmints" have of recent years made disproportionate inroads on them.

3. The closed season on deer has favored the increase of "varmints."

4. "Of course a lot have been shot" (but little stress was laid on this).

Despite all statements to the contrary the most relentless enemy of the Mule Deer is man. The persistence or elimination of the animals in the Yosemite region rests entirely with him. Since many of the deer in the Park proper move out into unpatrolled territory in winter it would seem that complete protection ought to be provided throughout this adjacent territory, at least until there is a sufficient natural increase to warrant reopening a hunting season there. At the present time, so far as the Yosemite National Park is concerned, the greatest potential value of the deer lies in their esthetic appeal; in observing them the visitor is thrilled with delight, and his mind and senses are acutely stimulated.


Animal Life in the Yosemite
©1924, University of California Press
Museum of Vertebrate Zoology

grinnell/mammals75.htm — 19-Jan-2006