Two environmentalists follow a herd of caribou across the tundra. From the National Film Board of Canada's YouTube channel.
Weights vary between subspecies, males varying from 125-275 kg and females 90 kg-139 kg. Newly born calves weigh 5-9 kg. Adult males have tall antlers with some vertical palmation (flat handlike lobes). Females have smaller antlers. Pelage (body covering) can vary from nearly white in some tundra populations to dark brown in woodland herds. Caribou hooves are broad and their pelage is dense with hollow hairs - adaptations for warmth and swimming. It is the strongest swimmer of the deer family as well as the best runner; both adaptations improve escape.
Single calves are born in May or June. Gestation is about 228-234 days and the rutting season is in October. Maximum longevity is about 13 years for males and 17 years for females. Age of first breeding (1 to 3 years of age) depends on body size hence summer nutrition is important. Caribou have several mates. Males seek nutritious forage to maximize body size for competition with other males. The reproductive fitness of females is enhanced by choosing safe habitats to raise her single calf. This dichotomy has resulted in females being more wary than males.
Caribou have broad food habits. Plant groups utilized include LICHEN in the winter and deciduous shrubs in the summer. Other groups utilized are mushrooms, grass and sedges, forbs, aquatics, ferns, mosses, horsetails and conifers.
In winter when caribou dig for lichens, they select open habitat sites with reduced snow cover rather the areas with maximum lichen biomass. Increased visibility decreases the chance of ambush and minimal snow cover maximizes escape speed. When foraging caribou are threatened, their escape route is to the nearest wind swept frozen lake where snow cover is reduced. Barren-ground caribou use the increased safety of frozen lakes for resting, ruminating and migrating.WOLVES commonly den, thus improving calf survival. Woodland females migrate generally less than 50 km, and disperse away from other females and alternate prey such as MOOSE. They seek high mountain slopes, islands or shorelines where they can reduce the probability of being found by predators or increase escape by swimming.
Many woodland caribou populations are now extinct including 4 herds in NATIONAL PARKS where logging is prohibited and anthropogenic disturbances are minimum. All the woodland caribou south of 60º N have been classified as threaten by the COMMITTEE ON THE STATUS OF ENDANGERED WILDLIFE IN CANADA (COSEWIC) in 2002. Two herds are listed as endangered - the southern most caribou in British Columbia and a small herd on the Gaspé Peninsula. Recent global warming has resulted in moose and deer increasing and moving north. Since the abundance of predators depends on the biomass of their prey, wolves, COUGARS and COYOTES are all expanding their ranges and increasing. Southern woodland caribou, unlike moose and deer, cannot coexist with such high predator numbers and will go extinct unless humans intrude. Peary caribou are also listed as endangered. Warming temperatures in the High Arctic (see CLIMATE CHANGE) have resulted in an increase of ice and hard snow crusts on vegetation leading to reduced pregnancies and increased starvation.
Aboriginal peoples harvest thousands of caribou, waiting each year for the long line of migrating caribou that trek in single file down trails followed for millennia. Some First Nations groups have been instrumental in protecting the habitat of certain caribou populations, for example in TUKTUT NOGAIT (NWT) and VUNTUT (Yukon) national parks.
Author A.T. BERGERUD
A.T. Bergerud, "Caribou," Chapter 13, Ecology and Management of Large Mammals in North America (2000), A.T. Bergerud, N. Luttich, and L. Camps, The Return of Caribou to Ungava (2008); George Calef, Caribou of the Barren Lands (1981).
Links to Other Sites
Old Crow: Land of the Vuntut Gwitch'in
An informative site about the geography, history, and culture of the Gwitch'in community of Old Crow. Also focuses on the historical relationship between the Gwitch'in people and the Porcupine caribou. Features great images, including one of a caribou fence and some that show caribou crossing the river. From Canada’s Digital Collections.
Prince of Wales Northern Heritage Centre
Explore the history, culture, and ecology of Canada's North at the website for the Prince of Wales Northern Heritage Centre. Check out "Inuvialuit Place Names" for interactive maps and interesting historical details about numerous sites throughout this vast region.
Canadian Biodiversity Website
A great information source for all budding biologists. Learn about biodiversity theory, natural history, and conservation issues. From McGill’s Redpath Museum.
Beverly and Qamanirjuaq Caribou Management Board
View one of the very informative maps from this online atlas devoted to the Beverly and Qamanirjuaq caribou range. Includes maps of caribou populations within the Thelon Wildlife Sanctuary and discussion papers about implementing measures that would protect local caribou herds. From the Beverly and Qamanirjuaq Caribou Management Board.
Lessons from the Land: Idaa Trail
Take a virtual tour along the Idaa Trail, a traditional canoe route of the Tåîchô (Dogrib) people in the Northwest Territories. Click on the names along the trail to learn about the history of each site. See the teachers' guide and other sections of the extensive Prince of Wales Northern Heritage Centre website for more information.
Porcupine Caribou Management Board
The website for the Porcupine Caribou Management Board. Check out the information on the caribou population, migration patterns, and more.
Caribou fences in the Vuntut National Park
An article about Gwich’in caribou fences in the Yukon. By Sarah Locke. Environment Canada Pacific and Yukon Regions Website.
Discover the heritage and traditions of the Innu through their stories and material culture. A Virtual Museum Canada website.
Species at Risk Public Registry
A searchable database of Canadian species at risk. Provides illustrated natural histories of each species as well as information about recovery programs, a glossary, and more. From Environment Canada.
The Early History of Woodland Caribou in British Columbia
A detailed report about the natural history of various caribou populations in British Columbia. From the Government of British Columbia. A PDF file.
Vuntut National Park of Canada
This illustrated Parks Canada website describes the ecology, geography, and history of Vuntut National Park of Canada.
An extensive teaching guide for learning activities about the natural history of mountain caribou. A PDF file. From the wildsight website.
Aurora Research Institute
Check the website for the Aurora Research Institute for news about their latest research projects.