Animal Life in the Yosemite
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SOUTHERN SIERRA MARMOT. Marmota flaviventer sierrae Howell

Field characters.—Body size about that of small badger; body stout; legs and tail short. Head and body 14-1/2 to 18-1/4 inches (370-464 mm.), tail 5-1/8 to 8 inches (130-200 mm.), hind foot 2-3/4 to 3-1/3 inches (70-84 mm.), ear from crown 2/3 to 1 inch (15-24 mm.); weight 4-1/3 to 7 pounds (1.94 to 3.2 kilograms). General coloration yellowish brown grizzled or 'ticked' above with white; chest and feet dull yellow; a yellowish area on side of neck; muzzle blackish, with narrow whitish cross-band just in front of eye. (See pl. 32a). Movements generally deliberate. Workings: Burrows in ground about 5 to 6 inches in diameter, beneath large boulders or at bases of trees or logs. Droppings: Dark brown or black, 3/8 to 1/2 inch in diameter, elongate, pointed at one end; scattered abundantly about burrows and on nearby flat-topped rocks. Voice: A single loud sharp whistle, sirk; sometimes repeated.

Occurrence.—Common resident, chiefly in Hudsonian Zone. Recorded from near Porcupine Flat and near Merced Lake eastward to Leevining Creek and to Silver Lake. Altitudinal range 7500 to 11,500 feet. Inhabits meadowland, especially where adjoined by rock slides or large boulders which afford protection for burrows. Soiltary. Diurnal.

The largest member of the squirrel tribe in the Yosemite region is the Sierra Marmot which inhabits the high Sierras between altitudes of 7500 and 11,500 feet. It is a ground and rock dwelling species, several times the size of the California Ground Squirrel. Besides the name marmot this animal is often called woodchuck and ground hog. The latter name is not altogether inappropriate, as it suggests the terrestrial habitat of the animal and also its stout body and rather heavy gait. The marmot is a species likely to be seen by any visitor to the higher parts of the region, as it is, like the ground squirrels, abroad during the daylight hours throughout the summer season.

In general demeanor the Southern Sierra Marmot is a lazy appearing animal. When not feeding, it spends much of its time sprawled out in the sunshine. If a person approaches a resting marmot on its rock the animal 'comes to attention' by 'gathering' its feet so that it may, if necessary, move off quickly. At the same time it gives its sharp whistle, which may be taken up and repeated by other marmots in the vicinity. If the person is not in clear view the marmot will sometimes stand up on its hind legs, after the manner of a 'picket-pin.' Then it may utter its whistle several times. If frightened enough to cause it to go below-ground, the animal usually does not appear again for some time. With a marmot that is foraging out in a meadow its first action, on the advent of danger, real or supposed, is to run for its burrow. Like a ground squirrel it usually takes further account of circumstances at a point just short of the entrance, before proceeding farther. When undisturbed a marmot moves at a slow walk. But when frightened it 'gallops,' bear-like, at about the rate that a man can run over the uneven surface of a mountain meadow.

The marmot and badger are sometimes confounded by the casual observer. They are of the same general size, with rather stout bodies and short legs and tails, and both are ground dwellers. But here the resemblance ends. The marmot has a face which is marked chiefly with yellow and brown (pl. 2); that of the badger is conspicuously black and white (pl. 24); the marmot has no white streak over the head while the badger has such a mark. The badger travels steadily, with its body very low and close to the ground; the marmot, especially when excited, gallops along, with undulatory movements of the body. The marmot is strictly vegetarian in diet, whereas the badger is a hunter and subsists upon flesh. The burrow of the marmot is usually under some rock or tree; whereas the badger as a rule sinks its burrow in wholly open ground.

The marmot population of the Yosemite region is to be found chiefly in the Hudsonian Zone and there most commonly about the larger meadows such as Tuolumne Meadows and the floor of Lyell Cañon. The species does, however, in places push down into the upper part of the Canadian Zone, and is found, for example, adjacent to Merced Lake and near Porcupine Flat. In these places, the lower limits of its range, it is but sparsely represented. On the east slope only a few individuals were observed by us below the hemlock belt (Hudsonian Zone). Two individuals taken at Silver Lake in 1916 were objects of marvel to the residents of Mono Valley, who declared that they had not previously seen the species there. The only other low record was of an individual observed in a big rock talus near some chinquapin brush on the Tioga Road in Leevining Creek Cañon at 8500 feet. One of the residents of Yosemite Valley, in 1914, told a member of our party that he had once seen a 'ground hog' in the pile of rock debris below Royal Arches on the floor of the Valley. On some of the main peaks of the Sierran crest, such as Dana and Conness, marmot droppings were found well above timber line, at 11,500 feet altitude. The highest point at which a marmot was actually seen by any member of our party was at 11,000 feet in the head of Lyell Cañon. At least three were heard at 11,500 feet on Parsons Peak.

The Sierra Marmot, like other ground dwelling squirrels, digs a burrow. This it uses as a retreat when seeking escape from enemies, as a place to spend the summer nights, and as a den in which to pass the long hibernating sleep of winter. In the choice of location, the escape from pursuit seems to be the most important consideration, for the marmot so locates its burrow that any enemy too large to enter the tunnel, for example, a coyote, could only with extreme difficulty get at the marmot in its underground retreat. Adjacence to a supply of food, and safety from flooding at the time of the spring thaw, probably also play a part in the choice of site, though these factors are not always apparent. Many of the local marmots have their headquarters in rock slides where the factor of safety is adequately met. (See pl. 32a). How far down within the shelter of these heaps of talus rocks the animals go to place their nests we do not know, as the exploration of rock slides is a thing yet to be accomplished by a naturalist. Other members of the local marmot population have their burrows under large granite boulders in meadowland or at the bases of large trees. In either situation an enemy would have great difficulty in digging out the inhabitant. The burrows in meadows are usually on mounds where the water from melting snow would not be likely to flow into the burrow. The diameter of the burrow is usually about 5 or 6 inches.

Those marmots which live in or along the margins of meadows have a source of food supply close at hand, for this species is more of a grass feeder than are the other members of the squirrel family. But individuals inhabiting the rock slides must either depend, in company with the Bushy-tailed Wood Rat and the Yosemite Cony, upon the plant growths, such as the red elder-berry, which occur among the rocks, or else venture out some distance to vegetation growing in the open.

A feature yet to be mentioned for the majority of marmot burrows is the presence close by, of a flat-topped rock on which the animal can sprawl out to bask in the sunshine, while at the same time keeping watch for the approach of enemies. Specially chosen rocks, used for the same purpose, are to be seen in the case of marmots which live in rock slides. On many of these rocks are large accumulations of droppings indicating occupancy through several successive seasons. (See pl. 32b). Likewise the smooth worn condition of many of the burrows, the absence of accumulations of earth about the entrances, and the lack of grasses and other plants there, all suggest that those locations have been in use for a number of years.

The food of the marmot consists of green vegetation including various herbaceous plants and grasses. The animal possesses no internal cheek pouches as do the ground squirrels and it is not known to store up a supply of food for winter use as does the cony. The lesser nutritive value of grasses as compared with seeds (used extensively by the squirrels) requires the marmot to take relatively large quantities of the former—and this it does, day after day, throughout the summer season. When the marmots emerge in the spring they are quite lean. As soon as green vegetation is available they feed to repletion, spending the daylight hours between successive feedings simply resting. This process results in a rapid accumulation of fat, which fills every space in the body and lies in great layers between the skin and muscle. This fat serves a double purpose; during the hibernating period it acts as an insulating layer to conserve bodily heat and also as fuel to maintain the life processes which are carried on, though at a lowered rate, during the period of dormancy.

The behavior of the species is indicated by the following account, written in the field after one of us had been watching a marmot for a half-hour or more at the head of Lyell Cañon one day in mid-July (the 20th, 1915).

The animal when first sighted had been feeding in meadow grass, but it took fright at my approach and ran to the shelter of a rock pile. By moving slowly, I was able eventually to get within 15 feet of it and to take several pictures. The animal would move out on some fiat-topped rock, remain there for a time with occasional slight changes of posture, and then disappear into the slide, to reappear soon at another similar location. Certain rocks seemed to be used as regular resting places, for the Marmot seemed inclined to stay about these. Often, although not always, the post taken was a slanting rock from which the animal could quickly tumble down into the interstices of the slide at the first intimation of danger. Once, for a short time, it reared up on its hind legs, using the tail to help support the body. Several times the Marmot uttered its sharp whistle, both when out in plain sight and when concealed from view amid the rocks of the talus heap. During the time that this marmot was under observation a Belding Ground Squirrel in the adjacent meadow was uttering its shrill alarm note, and this may have stimulated the Marmot to give its own note.

The seasonal activity of the Sierra Marmot extends from early spring until autumn. The date of first emergence is not known, as few if any people are in the high country early enough in the year to take note of such phenomena. Our own earliest date, June 28, merely indicates our first day within the range of the species. Breeding must take place early in the spring, as young animals, large enough to appear above ground, were trapped on July 10 (1915). Through the summer season the marmots are out every day, but as autumn draws near they are less in evidence, and soon all of them enter the long winter sleep. Our latest record is of a single individual observed near Ten Lakes on October 11 (1915). In late September but few were to be seen on Tuolumne Meadows where earlier in the year the species was common.

Little information is available concerning the home life of the marmot. The young are one-fourth to one-half grown by the middle of July and are then to be seen about the entrances of their home burrows. They probably attain sufficient size during the first season of their lives so that they can go forth before winter and dig their own burrows.


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

grinnell/mammals54.htm — 19-Jan-2006