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 (prairie dog), and Marmota (marmot and woodchuck). Citellus species are found in Asia, E Europe, and North America. In the Old World they are called sousliks. Other ground squirrel genera are found in Africa and S Asia. The approximately 30 North American species of Citellus are found W of Hudson Bay, from the Arctic Ocean to central Mexico. These ground squirrels have rounded heads, short ears and legs, and shorter, less bushy tails than tree squirrels. Their combined head and body length is 41/2 to 131/2 in. (11.4-33 cm) depending on the species; the tail is usually a third to two thirds as long. Most are gregarious, living in extensive underground burrows; they hibernate in colder parts of their range. Members of different species are found in prairie grasslands, arctic tundra, mountain meadows, open forest, desert, and scrub country. In some regions the ground squirrel is called gopher, a name more commonly applied to burrowing rodents of a different family. Primarily vegetarian in their diet, ground squirrels may become agricultural pests, but they destroy insects and mice as well as crops. Their tunnels cause landslides and erosion, but also serve to mix and aerate the soil. Ground squirrels are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Rodentia, family Sciuridae.