Arctic ground squirrels are the biggest and most northern-dwelling of all North American ground squirrels. Their fur is brown with white spots, except the underside is usually off-white. They molt twice a year, and their coat is typically more soft and fine, and a reddish-brown color in spring, turning to gray-brown and being stiff and thick when winter approaches. Arctic ground squirrels have stubby legs with four toes. They walk using all four legs.
The Arctic ground squirrel inhabits the Arctic parts of eastern Russia, and North America from Alaska to Hudson Bay and southwards to British Colombia. This animal occurs in Arctic tundra, forest clearings, open meadows, meadow-steppes and river valleys. It lives in sub-alpine and alpine zones up to altitudes of 1,400 meters, being often found on the edges of human settlements. The depth of permafrost (permanently frozen ground) needs to be at least one meter below the ground’s surface so that the squirrels are able to build their extensive burrows in order to survive.
Arctic ground squirrels are diurnal and live in colonies of 5-50 squirrels made up of a dominant male, several females plus young. They live in a complex system of burrows, with the entrances located under obstructions such as rocks, trees or logs, to hide them from predators. In spring territories are established, when the dominant male drives the other males away. The dominant male forms his territory to get access to food, females, favorable areas for hibernation and to discourage males in the area from mating with his group of females. A lactating female defends the area around her nursery in order to control local sources of food and to protect her young. The Arctic ground squirrel uses the scent from glands to warn others of its species away from its territory. It hibernates for about seven months, from September or October until the next March or April, emerging at a time which depends on the outside climatic conditions.
Arctic ground squirrels are omnivores, they mainly eat insects, birds’ eggs and sometimes each other’s young during the spring, and when winter approaches, berries, mushrooms, seeds, mosses and lichens are added to their diet. They also forage for dry grass and nuts to store for winter months.
Arctic ground squirrels exhibit both polygynous (one male mates with multiple females) and polygynandrous (promiscuous - both males and females have multiple mates) mating systems. The dominant male will usually be the father of the young, however, if he does not guard the female properly after mating, she may mate a second time with a different male. The mating season runs for about two weeks in late April soon after coming out of hibernation. Gestation is for three to six weeks, the female giving birth to one litter per year of six to eight young. A litter sometimes may contain up to 14. When born, kittens are without fur and teeth and have a covering of skin over their eyes. They develop quickly and are weaned when 28-35 days old, reaching independence at 6-7 weeks. Maturity is reached at about 1 year of age.
Arctic ground squirrels are hunted for their skin and meat for local trade, and by Northern American Inuit tribes, which use their skins for boots, clothing, and other items. The habitat of this species is being degraded by human expansion and increased agriculture. Droughts are also a threat, possibly due to natural change, not human activity. In addition, these squirrels are predated throughout their range by many carnivores.
There are no estimates of population numbers for Arctic ground squirrel. However, this species is locally abundant throughout their range and currently it is classified as Least Concern (LC) on the IUCN Red List.
The Arctic ground squirrel is a keystone species, with top-down as well as bottom–up impacts on local ecological processes. They act as an important food source for numerous mammals and birds. They are also important as soil engineers, as, in digging their burrows, they help turn over and aerate the soil, bringing nutrients up to the surface.