Rangifer tarandus
Caribou, especially barren-ground caribou, typify “the spirit of the north.” The beauty of these animals and the vast landscape they occupy are a compelling part of the mystique of Alaska. Caribou are found in alpine, tundra and forested areas in much of the Northern Hemisphere. All caribou, including reindeer, belong to one species, (Rangifer tarandus).
Large herds of reindeer, the domesticated form of caribou, roam parts of western Alaska. Caribou belong to the deer family and like all members of this family, they grow and shed their antlers each year. However, caribou are the only species in which both sexes grow antlers. The annual growth and shedding of the antlers differs between the sexes. Velvet knobs appear on the bulls in March, and their antlers grow rapidly over the summer so that by August they carry large velvet covered antlers up to 3 or 4 feet in length. The bony core is nourished by the blood soaked velvet which begins to strip off as the antler hardens by mid- September. These antlers are primarily sexual ornaments in preparation for the fall rutt, their breeding season. By November or December the older bulls begin to drop them and by February most of the younger animals have dropped their antlers as well. The female’s antlers develop from June to September but they will not drop them until the birthing time in spring. The cows antlers are more slender and much shorter. They produce a single calf which weighs from 10 to 20 pounds and is amazingly precocious, being able to travel with the mother within an hour of its birth.
There are actually 7 main subspecies of caribou in the Northern Hemisphere, each perfectly adapted to the harsh habitats they occupy. By far the most spectacular caribou populations that use the Arctic tundra and tiaga are the barren-ground caribou. These northerly herds have long migrations and huge numbers. Other populations in the state are smaller and have shorter migration routes. Many of these populations go through cycles from large to small and back again if allowed to respond naturaly to the various factors of their ecosystem.
Caribou are cloven-hoofed mammals. Their large concave hooves splay to carrying them across the snow and tundra they spend their lives on, and to shovel down through snow to reach lichen, a vital winter food. In summer the foot pads are large and the edges of the hooves worn flat so that the pad rests on the ground. In winter the hooves grow in length, the pads shrink and become tough, and the hair between the toes form tufts to cover the pads, protecting the foot from heat loss. They have other efficient ways of adapting to the cold. In winter most of the caribou retreat to the forest for shelter. Their pelage is of 2 types, long, stiff, hollow gaurd hairs which trap warm air next to the skin and a wooly like underfur. In the fall, caribou are chocolate brown with a white neck and rump, and frequently a white flank stripe. Their coat lightens as the seasons pass. There are two annual molts, the main one between July and early September. During this period, the long worn coat of both guard hairs and undercoat is shed in great patches.
Like most herd animals, caribou travel incessantly, moving among calving grounds, summer and winter range and breeding and fall range. Only during the mating season do all the various age-and-sex groups unite. Bulls typically weigh from 400 to 600 pounds with mature cows averaging around 200 pounds. Caribou rely almost completely on their sense of smell to detect danger. They can run up to 40-plus miles an hour and are excellent swimmers. A unique characteristic is the clicking sound produced by the slipping of tendons over sesamoid bones in their feet. Throughout the northern circumpolar lands, since the last ice age, caribou have provided for such basic needs as food, clothing, and shelter for many arctic and sub-arctic cultures. They continue to be an important part of the northern landscape and hopefully will remains so for all time to come.
