Caribou are members of the deer family, and the only deer species in which both sexes have antlers. The oldest known caribou fossil was found near Fort Selkirk in the Yukon and dates to 1.6 million years ago. Bone and antler tools found in the Old Crow and Dawson areas confirm that caribou have been important to the livelihood of humans in the Yukon for as much as 25,000 years, and they remain so today.
Most of the Yukon’s caribou are barren-ground caribou, like the huge Porcupine Caribou herd that migrates across the northern Yukon. However, the territory also has 17 small, isolated herds of woodland, or mountain, caribou, totaling about 25,000 animals. Several of the woodland herds cross over into the Northwest Territories or northern British Columbia. Both kinds of caribou survive mainly on lichens in winter, although they broaden their diets in summer to include a variety of grass-like plants, as well as willows and mushrooms.
Woodland caribou are larger than barren-ground caribou and travel much shorter distances. They spend most of the year in small groups that move between the boreal forest and the open mountain habitats where they go in summer to escape insects. In recent years, the melting of ice patches high in the mountains of the southern Yukon has revealed the accumulated droppings of thousands of years of caribou generations, along with the beautifully-preserved artifacts of the people who hunted them.
Caribou are well adapted to surviving extreme northern temperatures. Their bodies are compact. Appendages that stick out, such as muzzles, ears and tails, are thick, round and heavily furred. Their hair is hollow, which adds to its insulating value and also makes the caribou more buoyant when swimming across lakes and rivers. Their large hooves act like snowshoes to help them to travel over soft snow or boggy ground. The characteristic clicking sound made by moving caribou comes from the tendons slipping over the bones in their feet.