Caribou are large deer species inhabiting the northern reaches of the globe. These iconic animals are recognized for their impressive antlers and their ability to thrive in demanding landscapes. This article explores caribou’s physical attributes, habitats, behaviors, and how they differ from what are commonly known as reindeer.
Defining the Caribou
Caribou are members of the deer family, known for their robust build. Adult male caribou, or bulls, typically weigh between 159 and 182 kilograms (350-400 pounds), with some reaching up to 318 kilograms (700 pounds). Females are smaller, weighing around 80 to 120 kilograms (175-225 pounds). Their shoulder height ranges from 1 to 1.5 meters (3.3 to 4.9 feet).
Uniquely among deer species, both male and female caribou grow antlers, though males’ are larger and more branched. These antlers are shed and regrown annually, covered in a soft, vascular tissue called velvet before hardening. Their coat color varies by season, subspecies, and region, from dark brown in southern areas to nearly white in northern populations, providing camouflage. Caribou also possess large, concave hooves that spread widely to support them on snow and soft tundra, also functioning as paddles when swimming.
Where Caribou Live
Caribou inhabit diverse northern environments across a broad circumpolar distribution, including the Arctic tundra, boreal forests, and mountainous regions of North America, Greenland, and Eurasia. In North America, caribou are found from Alaska through Canada, reaching into the Yukon, Northwest Territories, and Nunavut. Some populations, like the woodland caribou, can be found as far south as 46 degrees north latitude.
They are well-suited to cold habitats due to several physical adaptations. Their double-layered fur, with a dense undercoat and hollow guard hairs, provides exceptional insulation against frigid temperatures. Specialized hooves, which change slightly with the seasons, help them navigate icy surfaces and dig through snow to access food. Their hairy noses and intricate nasal structures also help minimize heat loss during exhalation.
Life and Habits of Caribou
Caribou are herbivores, with diets shifting seasonally to utilize available vegetation. In summer, they consume a variety of plants including willow leaves, sedges, mushrooms, and flowering tundra plants. As autumn progresses into winter, their diet shifts to lichens (often called “reindeer moss”), dried sedges, and small shrubs. An adult caribou can consume up to five kilograms (11 pounds) of food daily.
They are known for undertaking some of Earth’s longest terrestrial migrations. Many herds travel thousands of kilometers annually between their summer and winter ranges; for instance, some Alaskan and Canadian herds migrate up to 1,350 kilometers (839 miles) annually. Movements are often triggered by changing weather, such as cold weather or snowstorms. Caribou typically live in large herds. Pregnant females lead migrations to traditional calving grounds, where most calves are born within days of each other in late May or early June. Calves develop quickly, able to stand within minutes of birth and travel with the herd within a day, which helps them survive against predators like wolves and bears.
Caribou and Reindeer: Understanding the Differences
Caribou and reindeer are the same biological species, Rangifer tarandus. The distinction between the two terms primarily relates to their geographical location and whether they are wild or domesticated. In North America, “caribou” refers to wild populations. Conversely, “reindeer” typically refers to wild or domesticated animals of the same species found in northern Europe and Asia.
Even within North America, domesticated Rangifer tarandus are commonly called reindeer. While they are the same species, subtle differences can arise due to domestication and varying environments. Domesticated reindeer tend to be shorter-legged, have slightly larger noses, and may exhibit variations in antler size and shape compared to wild caribou. Domesticated reindeer also often have a tamer disposition and are sometimes farmed for milk or used as draft animals. Wild caribou are known for extensive migratory patterns, a behavior less common in domesticated reindeer.