Richardson's ground squirrel (Urocitellus richardsonii), also known as the dakrat or flickertail, is a North American ground squirrel in the genus Urocitellus. Like a number of other ground squirrels, they are sometimes called prairie dogs or gophers, though the latter name belongs more strictly to the pocket gophers of family Geomyidae, and the former to members of the genus Cynomys. Taxonomy This squirrel was named after the Scottish naturalist Sir John Richardson. North Dakota is nicknamed the Flickertail state after the squirrel. The nickname Dakrat is derived from "Dakota Rat" and is a commonly used name around Minot, North Dakota and on Minot Air Force Base. Habitat Native to the short grass prairies, Richardson's ground squirrel is found mainly in the northern states of the United States, such as North Dakota and Montana, and in western Canada, including central and southern Alberta and southern Saskatchewan. The range of this animal expanded as forests were cleared to create farmland. They are not simply restricted to prairie; sometimes they adapt to suburban environments, causing them to be seen as pests because of the burrows they dig. It is not unusual to find squirrels digging tunnels under the sidewalks and patios of urban homes. Description Typical adults are about long. Weights vary greatly with time of year and with location: at emergence from hibernation the squirrels weigh between for females and between for males. But by the time they hibernate again, their weight may have risen to nearly . Males are slightly larger and heavier than females on average. They are dark brown on the upper side and tan underneath. The tail is shorter and less bushy than in other ground squirrels, and the external ears are so short as to look more like holes in the animal's head. Behavior is more like that of a prairie dog than a typical ground squirrel. The tail is constantly trembling, so the animal is sometimes called the "flickertail". Males have an average life expectancy of 3 years, while females average 4 years. However, in captivity some individuals may live for 5 to 7 years. Behavior Richardson's ground squirrels appear to live communally, but they organize their social structure around female kinship. A female Richardson's ground squirrel will tolerate the presence of closely related females, but are territorial towards other individuals. Individuals are territorial around their nest sites. The burrows of Richardson's ground squirrels are grouped