Holarctic ground squirrels

Urocitellus is a genus of ground squirrels. They were previously believed to belong to the much larger genus Spermophilus, but DNA sequencing of the cytochrome b gene showed that this group was paraphyletic to the prairie dogs and marmots, and could therefore no longer be retained as a single genus. As a result, Urocitellus is now considered as a genus in its own right.

All but two species are native to the northern and western parts of North America, from California and Minnesota through the north-western United States and western Canada; the Arctic ground squirrel inhabits Arctic terrain on both sides of the Bering Strait, while the long-tailed ground squirrel is exclusively found in Asia. The name of the genus is said to be derived from the Latin uro, meaning "tail" and citellus for "ground squirrel". The proper word for "tail" in classical Latin is cauda. Oura (οὐρά) is the ancient Greek word for "tail".