Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels, and flying squirrels. Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. The earliest known fossilized squirrels date from the Eocene epoch, and among other living rodent families, the squirrels are most closely related to the mountain beaver and to the dormice.
Picinae containing the true woodpeckers is one of three subfamilies that make up the woodpecker family Picidae. True woodpeckers are found over much of the world, but do not occur in Madagascar or Australasia.
The Anomaluridae are a family of rodents found in central Africa. They are known as anomalures or scaly-tailed squirrels. The six extant species are classified into two genera.
The eastern gray squirrel, also known, particularly outside of North America, as simply the grey squirrel, is a tree squirrel in the genus Sciurus. It is native to eastern North America, where it is the most prodigious and ecologically essential natural forest regenerator. Widely introduced to certain places around the world, the eastern gray squirrel in Europe, in particular, is regarded as an invasive species.
Ground squirrels are members of the squirrel family of rodents (Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known as marmots or prairie dogs, while the smaller and less bushy-tailed ground squirrels tend to be known as chipmunks. Together, they make up the "marmot tribe" of squirrels, Marmotini, a division within the large and mainly ground squirrel subfamily Xerinae, and containing six living genera. Well-known members of this largely Holarctic group are the marmots (Marmota), including the American groundhog, the chipmunks, the susliks (Spermophilus), and the prairie dogs (Cynomys). They are highly variable in size and habitus, but most are remarkably able to rise up on their hind legs and stand fully erect comfortably for prolonged periods. They also tend to be far more gregarious than other squirrels, and many live in colonies with complex social structures. Most Marmotini are rather short-tailed and large squirrels. At up to 8 kg (18 lb) or more, certain marmots are the heaviest squirrels.
Xerini is a tribe of ground squirrels occurring in Africa and Asia. With the tribes Marmotini and Protoxerini, they form the subfamily Xerinae. There are five living genera—Xerus, the unstriped ground squirrel; Euxerus, the striped ground squirrel; Geosciurus, the Cape and mountain ground squirrels; Atlantoxerus, containing the living Barbary ground squirrel of North Africa and some extinct species; and Spermophilopsis, containing the long-clawed ground squirrel of Central Asia.
The genus Sciurus contains most of the common, bushy-tailed squirrels in North America, Europe, temperate Asia, Central America and South America.
Bangs's mountain squirrel is a poorly known species of tree squirrel, that only lives in Costa Rica and Panama. It can be found in mountain rain forests at an altitude between 1,900 and 2,600 metres, and lives mainly in the tree tops, but sometimes on the forest floor as well. One of its habitats is at the summit of the Poás Volcano in Costa Rica, in a Clusia forest that is almost inaccessible to humans.
Smith's bush squirrel, also known as the yellow-footed squirrel or tree squirrel, is an African bush squirrel which is native to woodlands of the southern Afrotropics.
Sun squirrels, form a taxon of squirrels under the subfamily Xerinae and the tribe Protoxerini. They are only found in sub-Saharan Africa.
The groove-toothed flying squirrel or North Chinese flying squirrel is a species of rodent in the family Sciuridae. It is monotypic within the genus Aeretes. It is endemic to China, and occurs in Sichuan, Gansu, Hebei, and Beijing. Its natural habitat is temperate forests.
Beecroft's flying squirrel or Beecroft's scaly-tailed squirrel, is a species of rodent in the family Anomaluridae. Some authorities consider it to be monotypic within the genus Anomalurops. Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, and plantations. It is threatened by habitat destruction but is a common species with a wide range and the International Union for Conservation of Nature has rated its conservation status as being of "least concern".
The Barbary ground squirrel is a species of rodent in the family Sciuridae. It is monotypic within the genus Atlantoxerus. It is endemic to the Atlas mountains in Morocco and some parts in Algeria, and has been introduced into the Canary Islands. Its natural habitats are subtropical or tropical dry shrubland, temperate grassland and rocky areas where it lives colonially in burrows. It was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae.
The Kashmir flying squirrel is a species of rodent in the family Sciuridae. It is monotypic within the genus Eoglaucomys. It is found in India and Pakistan. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss. The Afghan flying squirrel is usually considered a subspecies.
The sculptor squirrel or Bornean pygmy squirrel is a species of rodent in the family Sciuridae. It was described by Michael Rogers Oldfield Thomas in 1898. It is monotypic within the genus Glyphotes. It is endemic to Malaysia and inhabits areas elevated at 600–1,700 metres (2,000–5,600 ft).
The African pygmy squirrel is a species of rodent in the family Sciuridae. It is monotypic within the genus Myosciurus. It is found in tropical rainforests in Cameroon, the Republic of the Congo, Equatorial Guinea, and Gabon. It is not considered threatened, but likely declines locally due to habitat loss. Together with the least pygmy squirrel of Asia, the African pygmy squirrel is the world's smallest squirrel measuring about 12–14 cm (4.7–5.5 in) in total length and just 15–18 g (0.53–0.63 oz) in weight, which is less than a typical house mouse.
The black-eared squirrel is a species of rodent in the family Sciuridae. It is monotypic within the genus Nannosciurus. This tiny squirrel is found in forests in Borneo, Sumatra and Java. Except for its striking whitish and black facial markings, the black-eared squirrel resembles the least pygmy squirrel.
The shrew-faced squirrel, also known as the long-nosed squirrel, is a species of rodent in the family Sciuridae. It is monotypic within the genus Rhinosciurus. It is found in forests in Peninsular Malaysia, Singapore, Sumatra and Borneo. This peculiar, terrestrial squirrel mainly feeds on insects and earthworms. It quite closely resembles a Tupaia treeshrew in appearance, but the shrew-faced squirrel can be recognized by its shorter gape, and shorter and more bushy tail.
The fiery squirrel is a rodent in the family Sciuridae. The taxon is endemic to the area south of the Orinoco River in the state of Bolívar, Venezuela.
The Xerinae comprise a subfamily of squirrels, many of which are highly terrestrial. It includes the tribes Marmotini, Xerini, and Protoxerini.
