The Barren-ground Caribou

Rangifer tarandus groenlandicus

Quick Facts

Common Name: Barren-ground Caribou

Scientific name: Rangifer tarandus groenlandicus

Size: Bulls weigh an average of 330 pounds and cows an average of 200 pounds. Calves are born weighing on average 13-15 pounds

Food Habits: They migrate between summer and winter ranges. In summer they eat the leaves of willows, flowering tundra plants, and mushrooms. In winter they switch to lichens, dried sedges, and small shrubs

Reproduction: Females begin mating at 28 months but males do not breed until 4-5 years old

Life Span: Most are relatively long-lived, with females living as long as 12–16 years and males for a few years less

climate change and caribou

Climate change is causing longer and warmer summers. This means longer growing seasons and better access to nutritious plants in the summer months. Due to the warmer temperatures, however, parasitic flies are able to torment the caribou. They will spend hours running to escape these parasites, which means they spend less time feeding. Winter warming produces an increase in the frequency of winter icing. Icing is caused by rain-on-snow or thaw-freeze events, and presents a real problem. During the winter they dig in the snow to get to food underneath. Icing traps food beneath an impenetrable layer of ice. These events have led to mass starvation of Arctic caribou and reindeer in the past.

Migratory caribou herds are named after their birthing grounds, in one case the Porcupine River, which runs through a large part of the range of the Porcupine herd. Though numbers fluctuate, the herd comprises about 218,000 animals that migrate over 1,500 miles a year between their winter range and calving grounds, the longest land migration route of any land mammal on Earth!


Did you know?

  • The Barren-ground Caribou is found in Alaska and the northern Yukon
  • Large herds move together between calving ground, summer feeding, and wintering grounds
  • Births are highly synchronized, with 90% of calves born during a 5 to 15 day period
  • They have scent glands on the base of their ankles that emit an odor to alert the rest of the herd to impending danger
  • The caribou has poor eyesight and hearing but is capable of  outrunning the wolf
  • Unlike many other members of the deer family, bull caribou do not control a harem of cows. Instead, they control a space around themselves and prevent other bulls from breeding females within their space

Title image thanks to Bauer, Erwin and Peggy, US Fish and Wildlife Service. Second image thanks to Juan Encalada via