Wikipedia
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; one species inhabits Arctic terrain on both sides of the Bering Strait, while the other is exclusively found in Asia. The name of the genus comes from the Latin words for "tail" (uro) and "ground squirrel" (citellus).