SQUIRREL

California ground squirrel (Spermophilus beecheyi) generally, any rodent of the family Sciuridae (order Rodentia); the name is sometimes restricted to the familiar, bushy-tailed, arboreal species. Squirrels are found almost worldwide, in a variety of habitats, including forests, deserts, plains, and tundra. There are about 50 genera and 260 species, among them the ground squirrels (see photograph), marmots, and chipmunks. Many squirrels are arboreal. Some (as marmots) are terrestrial; others (flying squirrels) glide from tree to tree by means of furry flaps of skin connecting their forelegs and hind legs. All squirrels have strong hindlegs and well-developed, hairy tails. They differ widely in colour and markings and vary in form from slender (flying squirrels) to stout (marmots). Total length ranges from about 10 centimetres (4 inches) in the African pygmy squirrel (Myosciurus pumilio) to about 90 cm in the giant squirrels (Ratufa) of Asia. All squirrels except the gliders are diurnal. Tree dwellers are agile, live in tree hollows or nests built of leaves and twigs, and are usually active throughout the year. Ground dwellers live in burrows, and many become dormant in winter (hibernate) or summer (estivate). Squirrels are primarily vegetarian and are noted for their fondness for seeds and nuts. Some species eat insects or supplement their diets with animal protein. Females bear one or more litters a year, of 1 to 15 young; gestation is 22 to 45 days. The genus Sciurus, with about 55 species found through most of Eurasia and the New World, includes such familiar arboreal squirrels as the Eurasian red squirrel (S. vulgaris) and the gray and fox squirrels (S. carolinensis and S. niger) of the east central United States. Members of this genus spend much time in the trees, occasionally descending to forage or to bury nuts in the ground. They are about 20 to 30 cm long, excluding tails of about the same length, and are generally gray, grayish to blackish brown, or reddish brown, with white to reddish brown underparts. Some, such as the Eurasian red squirrel, have tufted ears. The gray and fox squirrels, both common inhabitants of city parks and gardens, are edible, small game animals. They have been introduced into western North America and (gray squirrel) into Britain and South Africa. The Eurasian red squirrel, which in colder climates sometimes is hunted for its thick winter fur, is a native of forests from Britain to Japan. In parts of Britain, it has been replaced by the gray squirrel. The North American red squirrels (Tamiasciurus) are highly vocal, reddish brown animals that live primarily in coniferous forests and habitually collect large stores of pinecones for winter use. There are two species: the red, or spruce, squirrel (T. hudsonicus), found from Alaska to New Mexico and South Carolina; and the Douglas squirrel, or chickaree (T. douglasii), found from British Columbia to California. The former is about 20 cm long, without the 10- to 15-cm tail, and has white underparts; the Douglas squirrel is slightly smaller and has reddish brown underparts. There are a number of arboreal squirrels native to Africa. Notable species include: the giant forest squirrel (Protoxerus stangeri), a speckled brownish or blackish animal; about a dozen species of African striped squirrels (Funisciurus), with one or more longitudinal stripes on their backs; about 12 species of African bush squirrels (Paraxerus), which are speckled grayish yellow to bright reddish brown, with or without stripes; and sun squirrels (Heliosciurus), which are solid-coloured, sometimes greenish squirrels. There are also a number of tree-dwelling squirrels in Asia. Among them are: Asiatic striped palm squirrels (Funambulus), chipmunk-like, gray brown to blackish animals; four species of giant, or rock, squirrels (Ratufa), agile, variably coloured squirrels whose coats may be white, black, yellowish to reddish brown, or gray; and Oriental tree squirrels (Callosciurus, about 20 species), which are thick-furred, often brightly coloured inhabitants of eastern Asia. For terrestrial squirrels, see chipmunk; ground squirrel; marmot; prairie dog. For gliding squirrels, see flying squirrel.