, Two of the three subfamilies are of about equal size, containing between nearly 70 and 80 species each; the third is about twice as large. They do so by rotating their ankles 180 degrees, enabling the hind paws to point backward and thus grip the tree bark from the opposite direction. The oldest squirrel fossil, Hesperopetes, dates back to the Chadronian (late Eocene, about 40–35 million years ago) and is similar to modern flying squirrels. Many such baby squirrels have been rescued and fostered by a professional wildlife rehabilitator until they could be safely returned to the wild, although the density of squirrel populations in many places and the constant care required by premature squirrels means that few rehabilitators are willing to spend their time doing this and such animals are routinely euthanized instead. In: Zhang, Z.-Q. The paws, which include an often poorly developed thumb, have soft pads on the undersides and versatile, sturdy claws for grasping and climbing. Squirrels are familiar to almost everyone. 2020 National Geographic Partners, LLC. Genus Microsciurus – Drawf Squirrels of Central and South America (4 species)  When squirrels were almost completely eradicated during the Industrial Revolution in New York, they were later re-introduced to "entertain and remind" humans of nature. The Xerinae—the largest subfamily—are made up from the mainly terrestrial (ground-living) forms and include the large marmots and the popular prairie dogs, among others, as well as the tree squirrels of Africa; they tend to be more gregarious than other squirrels, which do not usually live together in close-knit groups.. The name of the genus is of Tupi origin (sai-mirim or gai-mbirin < sai 'monkey' and mirim 'small') and was also used as an English name by early researchers. Genus Paraxerus (bush squirrels) 11 African species. Some squirrels, however, also consume meat, especially when faced with hunger. They are predominantly herbivorous, subsisting on seeds and nuts, but many will eat insects and even small vertebrates. This further supports the hypothesis that the common ancestor of all squirrels, living and fossil, lived in North America, as these three most ancient lineages seem to have radiated from there; if squirrels had originated in Eurasia, for example, one would expect quite ancient lineages in Africa, but African squirrels seem to be of more recent origin. Prehensile-fingered climbers descend backward and generally with a walking type of leg sequence. They can jump across considerable gaps between trees. They also eat bark, eggs, or baby birds. Flying squirrels glide, extending their arms and legs and coasting through the air from one tree to another. The squirrel also belongs to the scuridae family and the rodentia order. Mothers may have several litters in a year, so most squirrel populations are robust.
 Morgart observed a white-tailed antelope squirrel capturing and eating a silky pocket mouse. The word "squirrel", first attested in 1327, comes from the Anglo-Norman esquirel which is from the Old French escurel, the reflex of a Latin word sciurus. More than 200 squirrel species live all over the world, with the notable exception of Australia. (in Finnish), "Timing of circadian activity in the flying squirrel in central Finland", "Cornwall squirrel 'pack' attacks boy, three", "When Squirrels Attack - A cautionary tale", "Class Mammalia Linnaeus, 1758. Some tropical squirrel species have shifted almost entirely to a diet of insects..  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. https://www.worldatlas.com/articles/5-types-of-north-american-squirrels.html Genus Callosciurus (Oriental, or tricoloured, tree squirrels) 15 Southeast Asian species. Squirrels in various places are the victims of squirrel poaching. Tails help these animals balance while running and climbing, and … As well, squirrel attacks on humans are exceedingly rare, but do occur. The tiniest squirrel is the aptly named African pygmy squirrelâonly five inches long from nose to tail. Milton, Katherine (1984): "Family Sciuridae". , Squirrels live in almost every habitat, from tropical rainforest to semiarid desert, avoiding only the high polar regions and the driest of deserts. The Sciurinae contains the flying squirrels (Pteromyini) and the Sciurini, which among others contains the American tree squirrels; the former have often been considered a separate subfamily, but are now seen as a tribe of the Sciurinae. Flaps of skin connecting limbs to body provide a winglike surface.  There has also been at least one 2005 report of squirrels preying on atypical animals, such as an incident where a pack of black squirrels killed and ate a large stray dog in Lazo, Russia. Sometimes groups of ground squirrels work together to warn each other of approaching danger with a whistling call. Genus Sciurus (tree squirrels) 28 non-African species. This gradual process of successful interaction is called synurbanization, wherein squirrels lose their inherent fear of humans in an urban environment. , In most squirrel species, the hind limbs are longer than the fore limbs, while all species have either four or five toes on each paw. , A variety of fossil squirrels, from the latest Eocene to the Miocene, have not been assigned with certainty to any living lineage.  The Old English word is of Common Germanic origin, cognates of which are still used in other Germanic languages, including the German Eichhörnchen (diminutive of Eichhorn, which is not as frequently used), the Norwegian ikorn/ekorn, the Dutch eekhoorn, the Swedish ekorre and the Danish egern. Saimiri is the only genus in the subfamily Saimirinae.
and Hoffmann, R.S. The distribution and diversity of such ancient and ancestral forms suggest the squirrels as a group may have originated in North America. Despite their name, these pests are commonly gray, brown, black, tan, and even red. In: Macdonald, D. Some authorities regard flying squirrels as a family (Pteromyidae), however, and a few species of anomalure are occasionally called scaly-tailed flying squirrels, but these rodents are classified in the family Anomaluridae. , The living squirrels are divided into five subfamilies, with about 58 genera and some 285 species. Tree squirrels are the types most commonly recognized, often seen gracefully scampering and leaping from branch to branch. (Oriental, or tricoloured, tree squirrels), (oil palm squirrels or African giant squirrels), (tufted, or groove-toothed, ground squirrel). The squirrel blended into the urban environment so efficiently that when synanthropic behavior stops (i.e. people do not leave trash outside during particularly cold winters), they can become aggressive in their search for food. Several species of squirrels make their home in Texas, but the one with the widest distribution is the fox squirrel. Gray squirrels live in northeastern and western states.  Premature death may be caused when a nest falls from the tree, in which case the mother may abandon her young if their body temperature is not correct. ), This article is about the squirrel family (Sciuridae) as a whole.  Wistrand reported seeing this same species eating a freshly killed snake. At Greenwood Wildlife Rehabilitation Center, north of Boulder, Colorado, injured and orphaned squirrels from all walks of life are fed, cared for, and eventually released back into the wild. The red squirrel is an arboreal, primarily herbivorous rodent. This Latin word was borrowed from the Ancient Greek word σκίουρος (from σκία-ουρος), skiouros, "shadow-tailed", referring to the long bushy tail possessed by many of its members.. The Ratufinae contain a mere handful of living species in tropical Asia. (Ed.) (ed. Whether they dwell high in a tree or in an underground burrow, female squirrels typically give birth to two to eight offspring. Tree squirrels belong to the subfamily Sciurinae; it and the subfamily Pteromyinae (flying squirrels) constitute the family Sciuridae of the order Rodentia. During these times, squirrels rely heavily on the buds of trees. ): Steppan, Scott J. and Hamm, Shawn M. (2006): Thorington, R.W.
, As their large eyes indicate, squirrels have an excellent sense of vision, which is especially important for the tree-dwelling species. Genus Sundasciurus (Sunda squirrels) 15 Southeast Asian species.
Tree squirrels are commonly seen everywhere from woodlands to city parks. The young are altricial, being born naked, toothless, and blind. Babies are blind and totally dependent on their mothers for two or three months. …with sharp claws, such as squirrels, climb by the alternate use of forelegs and hind legs; essentially, they hop up a tree. However, the population in … Adult squirrels can have a lifespan of 5 to 10 years in the wild. It prefers an open, parklike woods where large mature trees shade the forest floor and prevent the under-brush from flourishing, but it can adapt to a variety of forest habitats. Other species are ground squirrels that live in burrow or tunnel systems, where some hibernate during the winter season. Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness", 10.1671/0272-4634(2007)27[693:ANGOSR]2.0.CO;2, https://en.wikipedia.org/w/index.php?title=Squirrel&oldid=985805446, Taxa named by Gotthelf Fischer von Waldheim, Short description is different from Wikidata, Wikipedia indefinitely semi-protected pages, Creative Commons Attribution-ShareAlike License. Tree squirrels are the most easily recognizable group of squirrels, and three species are prominent throughout North America: the gray, fox, and red squirrels.
 Squirrels have been known to eat small birds, young snakes, and smaller rodents, as well as bird eggs and insects. Squirrels mate either once or twice a year and, following a gestation period of three to six weeks, give birth to a number of offspring that varies by species.