The Columbian ground squirrel (Urocitellus columbianus ) is a species of rodent common in certain regions of Canada and the northwestern United States. It is the second largest member of the genus Urocitellus, which is part of the tribe Marmotini, along with marmots, chipmunks, prairie dogs, and other holarctic ground squirrels. They are stout, with short dense fur, which is characteristically tawny across the bridge of the nose. Social encounters sometimes are initiated with kissing behavior and the most common activity above ground is standing at attention. Residing in mountainous terrain and high plains in northern latitudes, they hibernate for 8 to 9 months of the year in burrows, which may be used for many years. They are emaciated when emerging in the spring. The Columbian ground squirrel came to the attention of the scientific community through writings produced by Lewis and Clark, while 21st century molecular genetics has more finely illuminated its ties with other close relatives.
Columbian ground squirrels are one of the largest members of the genus. The largest is the Arctic ground squirrel. They have a relatively sturdy, robust build. The facial fur is bronze across the bridge of the nose. The fur along the back, legs, and feet is a more cinnamon buff, with darker fur closer to the body. There is a pale beige to buff ring of fur around the eye. The neck fur is gray along the sides of the cheeks. The flanks may be light beige or gray. They have a darker tail, with darker underfur and some lighter beige markings above and dark to grayish white below. Columbian ground squirrels hibernate most of the year and these long periods of torpor earned these animals the moniker "Seven Sleepers", since the rests last around seven months.
Columbian ground squirrels are found in Canada and the northwestern United States. They occur in the Rocky Mountains, from as far north as western Alberta and southeastern British Columbia. In the USA, they are found in the western parts of Montana, through central Idaho and into northern and eastern reaches of Washington. These squirrels live in alpine and subalpine areas, along the edges of meadows or on mounds where meadow flooding occurs. They are not found as frequently in rocky, fellfield, heather, or herbfield environments as they prefer meadows and grasslands. They occupy disturbed habitats including clear-cuts.
Columbian ground squirrels are social animals and live in large colonies. Females usually remain in the colony they were born in; males leave their home ranges and establish their own territtories. In Alberta (Canada), these squirrels hibernate around 250 days a year, and stay active only 69-94 days. Males start hibernating earlier than females. These animals are active during the day and sleep in their burrows during the night. They live in underground burrows, which may be used for many years. In the burrow used for hibernation, squirrels build a nest of grasses. Males store food for early spring as they usually emerge from hibernation before plants start growing. Females, emerge when first shoots of grass start growing and don't need to cache food. The most common activities for Columbian ground squirrels include standing at attention, feeding, and grooming. They avoid cloudy days, cold winds, and inclement weather. They are active during the hottest parts of the day. In order to greet each other, these animals will touch their mouths and noses together. This behavior resembles kissing and can last 1-5 seconds.
Columbian ground squirrels are herbevores. They feed on roots, bulbs, stems, leaves, flowers, seeds, and fruits.
Little is known about the mating behavior in Columbian ground squirrels. They start breeding during the early spring after winter hibernation. Females give birth to 1 litter per year consisting of 2-7 altricial young. The gestation period lasts around 24 days. Young are born naked, blind, and toothless but they develop very quickly. After 5-6 days, their weight has doubled. They are covered with dark silky hair by day 12 and around 17 days their eyes begin to open. Mothers nurse their young around 30 days. Pups may come out into the sunlight outside the den around day 21-24. After 4 weeks, they are able to leave the nest altogether but will remain with their mothers during the first winter of their lives. Males reach reproductive maturity at about 3 years of age. Females can start breeding in their second season.
Currently, there are no major threats to Columbian ground squirrels.
According to IUCN, the Columbian ground squirrel is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
