The diurnal Arctic ground squirrel lives in colonies consisting of a single dominant male, several females and young. It lives in an intricate system of burrows, with entrances placed under obstructions such as trees, rocks or logs, hiding it from predators (5) (8). Territories are established in spring, by the dominant male driving other males away (1) (7). The male will form a territory to gain access to sexually receptive females, food, favourable hibernation areas and to discourage other males from mating with the females within the area. A lactating female will defend the area surrounding its nursery to control food sources in the area and protect its young. The Arctic ground squirrel has scent glands which produce a scent to warn others away from its territory (7).
The Arctic ground squirrel hibernates for around seven months, from September to October until March or April, with the timing of emergence dependent on the climatic conditions outside the burrow (1) (2) (3) (4) (8). Within its burrow there will be hibernation chamber, which is slightly flattened and spherical in shape, and lined with dry grasses, fur, moss and sedges (4) (5). The chamber is so well insulated that in freezing conditions, the internal temperature is about 20 degrees Celsius higher than the temperature outside (4).
During hibernation, the body temperature of the Arctic ground squirrel is reduced to save energy, while its metabolism slows down to a third of the normal rate. The Arctic ground squirrel spends the months before hibernation accumulating food and fat on its body, as it typically loses around half its pre-hibernation weight throughout the winter months (4) (6) (8) (11).
An omnivorous species, the Arctic ground squirrel feeds mainly on insects, birds eggs and occasionally each other’s young throughout the spring, while berries, mushrooms, seeds, lichens and mosses are taken as winter nears (1) (4) (6) (8). Its diet is reflected in its genus name, ‘Spermophilus’, meaning ‘seed-loving’. While foraging for food to be eaten immediately, the Arctic ground squirrel will also forage for nuts and dry grass that can be stored for the winter months (1) (4).
Breeding occurs early in spring, to maximise the amount of time the pups have to gain weight before hibernation (4) (7). The paternity of the young will more than likely be the dominant male; however, if the male does not properly guard the female after mating, the female may mate again with a different male (3) (4).
The gestation period of the Arctic ground squirrel is three to six weeks, with the female producing one litter of six to eight young per year. Occasionally a litter may contain up to 14 young (1) (4) (7) (8). At birth, the Arctic ground squirrel has no fur or teeth and has skin covering its eyes. It develops rapidly, becoming independent after three to four weeks. Parental care is provided entirely by the female (4) (7).