Richardson's Ground Squirrel

Typical adults are about 30 centimetres (12 in) long. Weights vary greatly with time of year and with location: at emergence from hibernation the squirrels weigh between 200 and 275 g (0.441–0.606 lb) for females and between 350 and 450 g (0.77–0.99 lb) for males. But by the time they hibernate again, their weight may have risen to nearly 750 grams (1.65 lb). 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 three years, while females average four years. However, in captivity some individuals may live for five to seven years.

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, southern Saskatchewan, and southern Manitoba. 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.

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 closely together in colonies, and individuals give audible alarm calls when possible predators approach. Recent research has shown that in some cases, ultrasonic alarm calls are given, and are responded to by other members of the colony. Richardson's ground squirrels use two audible alarm calls, a high-pitched whistle and a 'chirp' call. The whistle is given in response to terrestrial predators, while the chirp is given in response to aerial predators such as hawks. Predators include hawks, owls, snakes, weasels, American badgers and coyotes.

Feeding. These animals are omnivores, eating seeds, nuts, grains, grasses and insects (especially crickets, caterpillars and grasshoppers). They stuff their cheek pouches with seeds, which are stored in the burrow and likely eaten in spring. They are also reported to cannibalize ground squirrels killed by road traffic.

Hibernation. Adult ground squirrels may hibernate as early as July, though in their first year, the young ground squirrels do not hibernate until September. …