Animal Life in the Yosemite
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LONG-EARED CHIPMUNK. Eutamias quadrimaculatus (Gray)

Field characters.—A large chipmunk (head and body about 5-1/2 inches, tail 3-3/4 inches long); usual chipmunk pattern of markings; ears proportionately taller than in any other species, and light spot behind base of each ear larger and more conspicuously clear white. (See pls. 3d, 33a). Distinguished from mariposae and senex by deep ruddy brown rather than grayish tone of coloration, as well as by taller ears and conspicuous white spot at base of same; may be separated from frater by larger size, taller ears and darker tone of coloration. (For comparative measurements see footnote 15, p. 177.) Voice: A sharp whsst or psst; also a low-pitched bock.

Occurrence.—Common resident in a narrow belt on west slope of Sierra Nevada between altitudes of 5000 and 7300 feet (upper part of Transition Zone and lower part of Canadian). Recorded from Sequoia, Hazel Green, and Chinquapin eastward to Indian Cañon and to junction of Sunrise and Clouds Rest trails. Lives about brush patches and logs, seldom going up in trees and then usually only a few feet above the ground.

The Long-eared Chipmunk is the most restricted in range of any of the chipmunks occurring on the west slope of the Yosemite region. It is found only in a narrow belt of territory between altitudes of 5000 and 7300 feet, hence chiefly in the upper half of the Transition Zone. Its range is almost complementary to that of the Mariposa and Allen chipmunks, the other two large sized species in the region, for the former does not anywhere go above 5000 feet, and the latter is seldom found far below the 7000-foot contour.

As suggested by the vernacular name, this chipmunk is noted for its rather tall and slender-appearing ears, the general effect of which is enhanced by the large conspicuous patch of pure white on the head just behind each ear. (See pls. 3d, 33a). The general pattern of markings on this species is the same as in other species but the effect is somewhat different, in that the Long-eared is more brownish and sharply streaked than the Allen and Mariposa chipmunks, and larger and darker toned with less conspicuous white stripes than the Tahoe Chipmunk.

This chipmunk lives about brush thickets and fallen logs and is much like the Allen Chipmunk in general behavior. Indeed in localities where the two occur together we could detect no appreciable difference in their habits. Both keep close to the ground, running over the surface and along logs, and, when frightened, both seek safety in dense brush or in hollows in logs rather than in trees. This feature alone is enough in most cases to distinguish these two larger animals from the Tahoe Chipmunk. But on a few occasions individual Long-eared Chipmunks have been noted well up in trees, once on a dead stub at a height of fifty feet or more above the ground.

The call note of the Long-eared Chipmunk is an incisive whsst or psst, thought to be sharper than that of the Tahoe Chipmunk, and usually given singly. There is also the hollow bock uttered at measured intervals.

At Hazel Green on May 15, 1919, one of us sat quietly for a time in a thicket of incense cedars and Douglas spruces and watched one of these chipmunks which had been running along and near a stake-and-rider fence which surrounded the adjacent meadow. The animal circled about the observer as close as three feet and not more than ten feet away, so that every movement could be clearly seen. The bright patches of white behind the bases of the ears made recognition easy and positive. At first the chipmunk gave the hollow bock a few times, accompanying each of the separated utterances by a forward jerk of the tail. Then the shrill explosive psst was uttered once or twice with less action of the tail. The movements were all quick and the chipmunk would freeze after each change of position, whereupon its variegated pattern fairly melted into the mixed background. This individual stayed on the ground or on logs and never ascended a tree. Others were seen the same day along the fence, usually running on some rail below the top one.

Along the 'short' trail to Glacier Point above the 5700 foot contour several chipmunks of this species were noted on October 9, 1914, running about over rocks and beneath the brush. The observer stopped and 'squeaked,' whereupon one of the chipmunks perched on a rock beneath a bush and began to wave his tail slowly back and forth. Presently he began to utter the low guttural chuck or bock at short regularly spaced intervals, thrashing the tail spasmodically from side to side or diagonally fore-and-aft in unison with the notes. The note, while low at first, later became clear and resonant, with a far-carrying quality. A movement on the part of the observer caused the chipmunk to whisk away through the brush.

In the warmer months of the year these chipmunks become active by sunrise. At Merced Grove Big Trees on June 10, 1915, four were out and running about near our camp at 6:10 A.M., just after the sun had appeared over the nearby ridge. The animals are active throughout the day, but usually disappear at sunset or as soon as the chill of evening sets in. The period of hibernation for this species is shorter than for any other save the foothill-inhabiting mariposae. Long-eared Chipmunks were out in force at Hazel Green on May 14, 1915, and had probably been out there for some time previously. When we visited Yosemite Point on October 30, 1915, we found the species still abroad in numbers; several brush-inhabiting chipmunks, probably of this species, were noted at Chinquapin on November 26, 1914. But on December 30, 1914, a visit to Gentrys where Long-eared Chipmunks are common in summer revealed none of the animals; they were then doubtless all in hibernation.

The breeding season of the Long-eared Chipmunk occurs at about the same time as does that of the other local chipmunks. A female taken at Merced Grove Big Trees on June 11, 1915, contained 4 small embryos, and another taken on the same date had 5 large ones. Two females taken June 10 and 24, respectively, in 1915, gave indications of having suckled young recently. We were not in the range of this species at the season when the young might be expected to appear, and by early fall we found the young-of-the-year indistinguishable in point of size from the adults.

Chipmunks, like many other wild animals, are often troubled with fleas and not infrequently they may be seen scratching themselves to get rid of the parasites. A Long-eared Chipmunk was watched one day while so engaged. The animal scratched vigorously, but that seemed not to bring the desired relief. He then resorted to a 'dry' bath. Pulling off some of the hard outer wood on a piece of decayed log the chipmunk repeatedly dragged his body through the rotted wood dust inside. The ground adjacent had just been freed of snow and was still wet; this fact probably accounts for the animal's use of the powdery rotted wood.

While coming down the zigzags on the Tenaya trail near Snow Creek on September 29, 1915, one of us found a rattlesnake which had been killed and left in the trail. The tail of a chipmunk was sticking out of the rattler's mouth. When we pulled out the body, which was head-down in the throat of the snake, it proved to be that of a Long-eared Chipmunk.

The food of this chipmunk consists of a variety of seeds and fruits occurring in the belt of snow bush (Ceanothus cordulatus). In addition, pine seeds are gathered where they drop out of the ripened cones on the ground. The cheek pouches of three individual chipmunks, collected at Gentrys and Aspen Valley, October 14 and 23, 1915, contained 1, 12, and 5 seeds, respectively, of the sugar pine.


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

grinnell/mammals62.htm — 19-Jan-2006