The Golden-Mantled Ground Squirrel In Crater Lake National Park
By Ralph R. Huestis
The golden-mantled ground squirrel, Citellus lateralis chrysodeirus Merriam, is one of the commonest mammals in Crater Lake National Park and probably produces more entertainment for visitors than all other types combined. This is not only because these animals are aggregated along the rim and in the campgrounds, where the greatest concentration of visitors takes place, but also because the squirrels are handsome in appearance, readily conditioned to the presence of human beings, and both appealing and comical in their behavior.
This species is commonly present in forested regions of Oregon from the Cascade mountains eastward and is especially prevalent in the ponderosa pine forests of the Cascade, Blue, and Wallowa Mountains. It is found, in these regions, from the edge of the sagebrush up into the white-bark pines at 8000 feet altitude. At Crater Lake these squirrels are present in all regions of the park including both Wizard Island and, on one occasion, on the Phantom Ship. The race occupying the Siskiyou mountains and therefore present in the Oregon Caves National Monument is described as subspecifically distinct and called the tawney-mantled ground squirrel, Citellus lateralis trinitatus Merriam.
The golden-mantled ground squirrel is a chunky little animal with a body about seven inches long and a well furred tail somewhat more than one-half the body length. Its legs are rather short and its ears relatively small but held tautly erect. The eyes are quite large for a burrowing animal and their size, combined with the erect carriage of the ears, give these squirrels an air of alertness and intelligence.
The flanks, the underside of the tail, and the head and shoulders are colored a rich, reddish brown. This is the coloring that accounts for the name golden-mantled. The back carries a broad median gray stripe, on each side of which are narrower contrasted stripes of black and white; two black ones with a white stripe between them. These contrasted stripes following the curve of the back while the squirrel sits up add greatly to its appearance.
Ground squirrels are not very fast animals and this squirrel compares unfavorably in speed with the chipmunks that occupy the same territory and with small enemy carnivores like the Cascade weasel, the Pacific marten, and the Cascade red fox. There is, however, an alertness in its postures and a briskness and energy in its movements that visitors find attractive. It seems probable that the hurried gallop from point to point which the squirrels alternate with a frozen pose or a brief nosing of the ground is highly adaptive. An animal in motion is likely to be seen and had better hurry if it moves at all. In addition, the time spent on exposed territory and between feeding periods is reduced to a minimum. These points may not be obvious to visitors, but they do see a hard-working little animal and admire the display of energy.
Comedy is supplied by the fact that the air of brisk alertness is not accompanied by any real evidence of great intelligence. In fact Citellus not infrequently plays the role of a busy fool; searching industriously for peanuts in empty hands when full ones beckon, and taking the trouble to investigate with a passing sniff any little object which may lie in his pathway on the rim walk pavement. He easily changes, too, from assured approach to precipitous flight with his tail above his back at about the angle a stove lifter projects from the lid, his broad little hams twinkling as his short hind legs spurn the dust.
Golden-mantled ground squirrels are said by Vernon Bailey to have but one brood a year of four to six or more young. Grinnell found an average of five young in five females in Yosemite National Park. The number probably increases with the age of the mother and as fully adult females have ten functional mammae they could easily accommodate larger broods. In 1936 a mother squirrel was observed moving nine little ones from a burrow in the rim campground and in 1938 the accidental death of a mother squirrel was followed by the exit of eight hungry little squirrels which were adopted and fed by rim campground visitors. Young are reported by Vernon Bailey to be born late in June or early in July. This checks with observations at Crater Lake National Park where in both 1937 and 1938 young squirrels emerged from burrows along the rim during the first week in August. The adopted brood mentioned in the previous paragraph seemed to be about three weeks old on August the eighth. A small newly-emerged squirrel was seen coming out of a burrow in the rim campground as late as September 3, 1937.
The episode mentioned above in which a mother squirrel moved young from a burrow, part of which had been collapsed by a car, shows that these animals share the typical mammalian habit of moving young to less menaced positions. In August 1938 Dr. Fred Miller, park physician, observed the moving of six young from a nest somewhere in the Community House through the door to a refuge somewhere outside the building. The young were carried by the body with ventral surface toward the mother's mouth and curled around the mother's head just as young deer mice are under similar circumstances.
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