Also found in: Dictionary, Thesaurus, Medical, Idioms, Wikipedia.


name for small or medium-sized rodentsrodent,
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 squirrelground 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 (prairie dog), and Marmota
..... Click the link for more information.
, chipmunkchipmunk,
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.
, marmotmarmot,
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.
, woodchuckwoodchuck
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. Its heavyset body is about 2 ft (60 cm) long, excluding the 6 in.
..... Click the link for more information.
, prairie dogprairie 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 squirrelflying 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.


Squirrels are classified in the phylum ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
..... Click the link for more information.
, subphylum Vertebrata, class Mammalia, order Rodentia, family Sciuridae.


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



a mammal of the genus Sciurus of the family Sciuridae of the order Rodentia, distributed in the forests of Europe, Asia, and America. There are about 50 species. Squirrels are adapted to an arboreal mode of life. The length of their body reaches 28 cm. Their fur is usually thick and on certain squirrels, fluffy. Their color ranges from bright red to gray and black; many species are variegated. There are two species in the USSR—the pine squirrel and the Persian squirrel.

The pine squirrel (S. vulgaris) is found in the northern forest and forest-steppe zones that extend to the forest tundra. They are most numerous in the dark pine and larch taiga and in mixed forests. Feeding on the seeds of pine trees, acorns, nuts, berries, and occasionally insects and bird eggs, they store food for the winter. Pine squirrels are diurnal animals. They build nests in trees from lichens, moss, bast, and twigs or settle in tree hollows. There are usually two (sometimes three) litters a year yielding five to ten baby squirrels. The number depends on the yield of pine seeds; in lean years pine squirrels undertake massive migrations. They are one of the major objects of the fur industry in the USSR (in the taiga zone of the European part, the Urals, and Siberia).

The Persian squirrel (S. anomalus) is found in the forested regions of the Trans-Caucasus. Because of their small number and sparse coarse fur, these squirrels have no economic value.


Ognev, S. I. Zveri SSSR i prilezhashchikh stran, vol. 4, Gryzuny. Moscow-Leningrad, 1940.
Naumov, S. P., and N. P. Lavrov. Biologiia promyslovykh zverei i ptits SSSR. Moscow, 1948.
Mlekopitaiushchie fauny SSSR. Moscow-Leningrad, 1963.


(vertebrate zoology)
Any of over 200 species of arboreal rodents of the families Sciuridae and Anomaluridae having a bushy tail and long, strong hind limbs.


1. any arboreal sciurine rodent of the genus Sciurus, such as S. vulgaris (red squirrel) or S. carolinensis (grey squirrel), having a bushy tail and feeding on nuts, seeds, etc
2. any other rodent of the family Sciuridae, such as a ground squirrel or a marmot
3. the fur of such an animal
References in classic literature ?
BUT when the other squirrels heard that song, they rushed upon Timmy Tiptoes and cuffed and scratched him, and upset his bag of nuts.
Timmy rolled over and over, and then turned tail and fled towards his nest, followed by a crowd of squirrels shouting --"Who's-been digging-up MY-nuts?
Next morning she ventured back to the nut-bushes to look for him; but the other unkind squirrels drove her away.
Utilization of fungi by the gray squirrel is reported to occur most during spring and summer (Carraway and Verts 1994), whereas fox squirrels utilize fungi during the summer and winter (Koprowski 1994).
When Gopher Joe asked Spermanidas, the Spartan Squirrel to help in their anti Gardener campaign, he regretfully refused also, because it was time to celebrate the Hibernation Moon Festival, giving thanks to the Earth for food and asking to be kept safe in their burrows for another winter.
Whole scientific careers have gone into understanding why a harmless handful of fluff like a California ground squirrel taunts rattlesnakes.
Squirrel fibromatosis, which is the pathological manifestation of squirrel fibroma virus, was first reported in free-living squirrels in the United States in 1953 (Kilham et al.
In fox squirrel (Sciurus niger) pre-copulatory displays, males use different tail flicks to signal aggressive vs.
As messy as a nesting squirrel can be, the biggest threat from a home invasion is the possibility of a fire.
A member of the class of 1967, the Delmarva Peninsula fox squirrel (Sciurus niger cinereus) was among the first animals considered to be threatened with extinction.
As well as displacing red squirrels from their habitat, grey squirrels also carry the squirrel pox virus, which they have spread to the reds.
Rachel Miller, Red Squirrel field officer at the Wildlife Trust for Lancashire and North Merseyside, said: "The research found that one red squirrel definitely survived the pox and it was released back into Ainsdale where it was originally found.