The habits of the western gray squirrel are modified by its arboreal existence. Homes consist of holes in hollow trees or outside nests of sticks and twigs. It is extremely active in trees and travels from tree to tree on branches that seem scarcely strong enough to bear the weight of so large an animal. The oak woods in Washington are usually rather open and the trees more scattered than is the case in coniferous forests. Consequently gray squirrels must more often descend to the ground than Douglas and red squirrels. On the ground, western gray squirrels travel in smooth leaps each of two feet or more in length. The long tail is held out behind and "follows through" the animal's leaps in a remarkable way. The tip of the tail may be descending from the previous leap while the animal's fore parts are already at the height of a new jump. This results in a "flowing" movement that is extremely graceful. The squirrel may stop momentarily to dig in the ground or search for an acorn. At such times the tail is immediately switched up, over the back.
The western gray squirrel is able to drop unharmed for considerable distances. Near Fort Lewis, Pierce County, a gray squirrel was cornered in a tall fir tree and an agile friend volunteered to climb the tree. The squirrel ascended to the very topmost branches. When only a few feet separated them the squirrel leaped far out into the air. Its legs were stretched out stiffly, the tail was extended and the body slightly arched. It struck the ground with an audible thud and bounced fully 18 inches. At the height of its bounce, the squirrel's legs began moving rapidly, and it struck the ground the second time at a full run.
The principal food is acorns, although the seeds of the Douglas fir and probably other conifers are eaten. Four embryos were found by Victor B. [Scheffer] in a specimen from Klickitat County on March 20, 1939.
Sciurus carolinensis hypophaeus [Merriam]
Eastern gray squirrel
Sciurus carolinensis hypophaeus [Merriam], Science, 7:351, April 16, 1886.
Type.—Obtained at Elk River, Sherburne County, Minnesota.
Description.—Size large, slightly smaller than the western gray squirrel; color of upper parts less silvery, more reddish, especially on the dorsal area and top of the tail.
Remarks.—The eastern gray squirrel was introduced at Woodland Park, Seattle, in 1925. The original stock (7 pairs) came from Minneapolis, Minnesota. It has spread through the nearby woods, around Green Lake, [Cowan] Park, and to the woods on the University of Washington Campus. Occasional individuals are found outside the city limits, but the species seems not to spread away from the city.