Caribou are the largest members of the reindeer family (Rangifer tarandus) and are native to the arctic and sub-arctic regions of Siberia, North America and Greenland. Reindeer, which are traditionally herded in northern Europe and Eurasia, were introduced into Alaska in 1892. Although some herding of reindeer continues in Alaska today, many of the introduced reindeer interbred with caribou. The four caribou subspecies barren ground, Peary's, tundra and woodland ÂÂdiffer greatly in range, size, coloration, behavior, food habits and habitat use.
Caribou are a medium-sized member of the deer family and stand about 3.5 feet tall at the shoulder. Females (cows) can weigh up to 300 pounds, while large males (bulls) are about twice that size. Most caribou are medium-brown or gray, but coloration varies widely from nearly black to almost white. Their winter coat is somewhat lighter than their summer coat.
Caribou are the only deer species in which both males and females have antlers. Their antlers, which are shed every year, have a long, sweeping main beam up to five feet wide. Each side has one or two tines, or branches, and each tine may have severalpoints. The larger racks of caribou bulls are considered trophies by big-game hunters.
Caribou have special adaptations that allow them to survive their harsh arctic environment. Long legs and broad, flat hooves help them walk on snow and on soft ground such as a peat bog. A dense woolly undercoat overlain by stiff, hollow guard hairs keeps them warm. Caribou dig for food using their large, sharp hooves.
The average lifespan of an adult caribou is eight to ten years. They reach maturity at about three years. As with most deer species, male caribou fight each other for a harem of five to 40 cows. This sparring, called rutting, occurs in the fall. Injuries in this natural quest for dominance are rare, although occasionally the bulls' antlers lock together and both animals die.
A single calf is born in the spring. Unlike most deer, caribou young do not have spots. They are able to walk within two hours of birth and are weaned gradually over several months. After calves are born, females with newborns gather into nursery bands and separate from the rest of the herd. Gradually, the bulls and barren cows rejoin the calving cows at the calving grounds. These larger groups of caribou offer some protection for the calves from predators such as wolves, bears and lynx.
Caribou feed on sedges, grasses, fungi, lichens, mosses, and the leaves and twigs of woody plants such as willows and birches.
Although some herds stay on the cold tundra all year, most caribou have distinct summer and winter ranges. The large northern herds migrate over long distances, frequently crossing large, swift-running streams and rivers. Consequently, even caribou young are extremely strong swimmers.
Insect bites are a particular nuisance for caribou. When mosquitoes are numerous, a caribou may lose up to half a pint of blood a day. In coastal areas, they seek temporary relief by submerging themselves in water. They may seek windy hilltops, dry, rocky slopes, or snowfields if they do not have access to a coastal area. Barren ground caribou have been known to stampede in attempts to escape the ravages of mosquitoes, warble flies or nostril flies.
Caribou were once essential to the survival and livelihood of native peoples of the Arctic. Natives used caribou meat, milk and organs for food. Hides provided material for clothing and shelter, and bones, antlers, and sinews were used to make tools, tableware, and handicrafts. However, though caribou remain a subsistence food resource, other uses have declined as native populations have become more technologically advanced.
Though caribou in North America were once found as far south as Lake Superior, today they are completely absent in New Brunswick, Nova Scotia, Maine and Minnesota, mainly due to changes in plant growth since the last glaciers receded 10,000 years ago. Remnant caribou populations in these areas were susceptible to the encroachment of European settlers and subsequent changes in the habitat brought about by logging, farming and fire suppression. The early settlers also hunted caribou heavily for food.
Only one population of caribou is left in the lower 48 states ÂÂthe Selkirk Mountain herd which ranges from Canada into northern Idaho. Outside Alaska, this herd of woodland caribou is the last of its kind in the United States. In 1983, the U.S. Fish and Wildlife Service placed this population on the endangered species list, giving it protection under federal law. Endangered status means the woodland caribou is considered in danger of extinction within that part of its range.
Canada and the State of Idaho cooperatively manage the Selkirk Mountain herd through monitoring and reintroduction of more woodland caribou to enhance the population. In Alaska, the U.S. Fish and Wildlife Service, through its Arctic National Wildlife Refuge, protects large portions of the range of the Porcupine caribou herd, in particular the herds sensitive calving grounds.
Although the Porcupine herd is not considered endangered, in 1987, the United States and Canada finalized a formal agreement for the conservation and management of this group of majestic caribou.
