squirrel, name for small or medium-sized rodents rodent, member of the mammalian order Rodentia, characterized by front teeth adapted for gnawing and cheek teeth adapted for chewing. The Rodentia is by far the largest mammalian order; nearly half of all mammal species are rodents.
..... Click the link for more information. of the family Sciuridae, found throughout the world except in Australia, Madagascar, and the polar regions; it is applied especially to the tree-living species. Tree squirrels range from the size of a mouse to the size of a house cat and vary greatly in color; some Asian tree squirrels are brilliantly patterned. In addition to the tree squirrels, the family includes the ground squirrel ground squirrel, name applied to certain terrestrial rodents of the squirrel family. In North America the name refers to members of the genus Citellus and sometimes to the closely related genera Tamias ( chipmunk ), Cynomys
..... Click the link for more information. , chipmunk chipmunk, rodent of the family Sciuridae ( squirrel family). The chipmunk of the E United States and SE Canada is of the genus Tamias. The body of the common Eastern chipmunk, Tamias striatus, is about 5 to 6 in.
..... Click the link for more information. , marmot marmot, ground-living rodent of the genus Marmota, of the squirrel family, closely related to the ground squirrel, prairie dog, and chipmunk. Marmots are found in Eurasia and North America; the best-known North American marmot is the woodchuck , M.
..... Click the link for more information. , woodchuck woodchuck or groundhog, common name of a North American species of marmot , Marmota monax. This large rodent is found in open woods and ravines throughout most of Canada and the NE United States.
..... Click the link for more information. , prairie dog prairie dog, short-tailed, ground-living rodent, genus Cynomys, of the squirrel family, closely related to the ground squirrels, chipmunks, and marmots. There are several species, found in the W United States and N Mexico.
..... Click the link for more information. , and flying squirrel flying squirrel, name for certain nocturnal tree squirrels adapted for gliding; they do not actually fly. Most are found in Asia, but one species of the genus Pteromys extends into SE Europe and the two species of Glaucomys are found in North America.
..... Click the link for more information. .

Tree Squirrel Characteristics and Behavior

The so-called typical tree squirrels are members of the genus Sciurus, with about 40 species distributed throughout forested regions of Eurasia and the Americas. These are day-active animals with slender bodies, sleek, thick fur, and bushy tails. Their coats are black, gray, brown, or reddish above and light-colored below. Light, swift, and agile, tree squirrels leap from branch to branch and scurry up and down trees using their sharp claws to dig into the trunk; they always descend head first. The tail is used as a rudder when the animal leaps and as a parachute when it drops. They have excellent sight, including good color vision. The handlike forepaws are used for holding food. Tree squirrels make nests in holes in trees or on branches. They spend much time on the ground, foraging for fruit, nuts, and insects; they also sometimes eat eggs, young birds, and smaller mammals. Members of many species store food for the winter in holes or buried in the ground; they locate these stores by means of smell. They do not hibernate.

Types of Tree Squirrels

Sciurus species include the Eurasian red squirrel, S. vulgaris, and the North American gray squirrels, fox squirrel, and tufted-eared squirrels. Gray squirrels have tails about as long as the combined head and body length. The eastern gray squirrel, S. carolinensis, common in the eastern half of the United States and extreme southern Canada, is up to 20 in. (51 cm) in total length, 5 in. (13 cm) high at the shoulder, and weighs 1 to 1 1-2 lb (450–700 grams). It has been introduced in Europe. The western gray squirrel, S. griseus, of the U.S. West Coast, is slightly larger. The fox squirrel, S. niger, is the largest North American squirrel, reaching 29 in. (74 cm) in total length; its head is somewhat square. It displays great variation in its fur color but is commonly light brown. It is found in the eastern half of the United States, excluding the extreme northeast. Although its numbers have been greatly diminished by hunting and clearing, it is still common in some areas. It has also been introduced in city parks in western states. The tufted-eared squirrels, also called tassel-eared, or Abert, squirrels, are very distinctive, with tall plumes of hair on their ears. They inhabit yellow pine forests of the Colorado Plateau. One variety, the Kaibab squirrel, is found only on the northern rim of the Grand Canyon. North American red squirrels, also known as pine squirrels and chickarees, are species of the genus Tamiasciurus. They are small and noisy, about 12 in. (30 cm) long and 3 1-2 in. (9 cm) high, weighing 5 to 10 oz (140–280 grams). They are found in the pine forests of Alaska, Canada, and the N and W United States. Other genera of arboreal squirrels are found mostly in Africa, S and SE Asia, and Central and South America.

Classification

Squirrels are classified in the phylum Chordata Chordata (kôrdā`tə,–dä`–)
..... Click the link for more information. , subphylum Vertebrata, class Mammalia, order Rodentia, family Sciuridae.

Bibliography

See D. MacClintock, Squirrels of North America (1970).

squirrel

Any of about 260 species in 50 genera (family Sciuridae) of mostly diurnal rodents found almost worldwide. Many species are arboreal; some are terrestrial. All species have strong hind legs and a hairy tail. They vary widely in colour and form and range in total length from the 4-in. (10-cm) African pygmy squirrel to the giant squirrels of Asia, about 35 in. (90 cm) long. Tree dwellers live in a tree hollow or nest, and most are active year-round. Ground dwellers live in burrows, and many become dormant in winter (hibernate) or summer (estivate). Most species are primarily vegetarian and are fond of seeds and nuts; some eat insects or supplement their diet with animal protein. See also chipmunk; flying squirrel; ground squirrel; marmot; prairie dog.