Arctic Ground Squirrel

The Arctic ground squirrel (Spermophilus parryi, Spermophilus means "seed loving") is a large rodent belonging to the squirrel family (Sciuridae), rodent order (Rodentia). Known as a "gopher" to most Yukoners and a "tsik-tsik" by the Inupiat Eskimos in Alaska, it is the largest and most northern of New World ground squirrels. The Arctic ground squirrel inhabits meadow-steppe, tundra, and mountain-tundra landscapes in the Northeastern Palearctic (from the Verkhoyansk Ridge in the east and to the south to the southern extremity of Kamchatka and environs of Okhotsk city), as well as Alaska and northeastern Canada, and generally hibernates from April to September.

Adult males have a body length of 26-29 cm, a tail 8.9-11 cm long, and a body mass of 620-950 g. Females are distinguished by smaller sizes. The ears are short, slightly fur-trimmed, and positioned a little forward over the fur-covered head. The ground squirrel has cheek pouches. There are indistinct or clear small light speckles on its reddish-brown or yellow-brown back. It has strong front forelegs that are adapted for digging.

The Arctic ground squirrel is found from sea level to mountain tundra zone, Alpine, and sub-Alpine meadows above the treeline. Its settlements are mainly arranged in sandy banks of well-drained river terraces or moraines, since good drainage increases the depth to permafrost through which the squirrels cannot dig, and sedge and cereals herbage grow. In mountains, the ground squirrel inhabits mainly steppe meadows formed by sparse vegetation composed of xerophyte mixed grasses and cereals growing on flat slopes and borders of south-facing intermountain valleys. Ground squirrels settle in sparse cedar groves and edges of sparse larch forests, but avoid continuous bush brushwood or forested areas. It is often found on the territory of small northern taiga and tundra villages.

Ground squirrels typically live in colonies of 5-50 squirrels. Burrows are easy to find by earth mounds

Arctic ground squirrel (Spermophilus parry!) by its burrow, Nunavut, Canada.

Copyright Norbert Rosing/National Geographic Image Collection

Arctic ground squirrel (Spermophilus parry!) by its burrow, Nunavut, Canada.

Copyright Norbert Rosing/National Geographic Image Collection near holes leading to underground passages. The entrance to the hole is often inclined and rarely vertical, and has up to ten entrances per burrow. Burrows are not more than 50 cm deep and generally positioned above permafrost. The passage widens to one or two nesting chambers lined with split sedge and cereals stems and leaves for insulation. Two to four blind alleys for feces are built not far from the chambers. Large winter food reserves have not been revealed. In colonies, separate holes are linked to each other and with temporary protective refuges—blind alleys 30-50 cm long—by means of surface paths.

The Arctic ground squirrel lives in extremely cold environments, and gets through the harsh winters by incorporating hibernation into its life cycle. Ground squirrels hibernate seven months out of the year, retiring to their hibernation chambers with permanent snow covering in early September and waking in mid to late April, often into snow. In these conditions, heat is generated and lost rapidly. It is not uncommon for female juveniles to lose between 30% and 40% of their body weight during hibernation. Ground squirrels hibernate upright, with their heads tucked down and tails thrown over the head. The squirrel then allows its body temperature to fall close to of its hiber-naculum for weeks at a time. During hibernation, its body temperature drops to almost 0°C, and the back part of its body can cool down to -20°C. It is the only known mammal capable of lowering its body temperature to below freezing. Periodically it briefly rouses and warms itself up to near its normal body temperature of 36.4°C before going back into hibernation.

The Arctic ground squirrel is primarily herbivorous, favoring such foods as ground parts of plants, roots, rhizomes, sedge and grass seeds, small bushes, mushrooms, and berries. However, with a lack of vegetation forage, this squirrel eats insects and small rodents, including its own kind. It generally feeds around high noon and often stuffs its cheek pouches full of leaves or seeds to take back to its den for later consumption. Foraging is interrupted by frequent stops to sit up and check for danger. Generally, the ground squirrel uses its teeth to cut down vegetation, and then holds the food between its paws to eat so that it may keep its head up to watch for predators.

Females give birth to one litter in late May or early June, with 5-14 young squirrels (on average, 5-7). Blind, naked, and weighing less than one ounce, the young rapidly increase in body weight, and at 20 days their eyes open. By 30 days, their fur resembles adults and they begin to explore the world above ground. They achieve the size of adult squirrels by the fall and take part in reproduction the following year.

Despite the fact that there is continuous daylight during the summer months, this squirrel is diurnal. Because there is continuous light and very little vegetative cover available in their habitat, ground squirrels move with their bodies pressed close to the ground to make themselves less obvious to predators. This type of movement has been termed "tundra glide."

Social interactions include both physical and vocal communication. Physical encounters are characterized by either nose-to-nose contact or pressing together of body parts. This contact is a test of receptivity and can often lead to fights. The second type of interaction, vocal communication, has led humans to give this squirrel the nickname "tsik-tsik." These "tsik" sounding calls generally alert others in the territory to the presence of nearby predators. There are even different kinds of calls for different kinds of predators. Low gutter chatters are used to indicate land-borne predators whereas short "band whistle" chatters indicate avian predators.

The Arctic ground squirrel is hunted for its fur: in northern Alaska, women make parkas (and hence they are sometimes known as parka squirrels). Fur harvesting can reach one million squirrels annually. In some regions, ground squirrels carry and keep human infectious diseases. While no longer hunted for food, they are an important link in the food chains for predators important in the fur trade (ermine, polar fox, fox, and others).

Vladimir Vasiliev

Further Reading

Hubbs, Anne & Rudy Boonstra, "Effects of food and predators on the home-range of Arctic ground squirrels." Canadian Journal of Zoology, 76 (1998): 592-596 Tavrovsky, V.A. et al. (editors), Mlekopitaiuschchie Iakutti,

Mammals of Yakutia, Moscow: Nauka, 1971 (in Russian) Woods Jr., S.E., The Squirrels of Canada, Ottawa, Canada: National Museums of Canada, 1980

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