Common Name: Caribou
Also referred to as: Reindeer
Genus species: Rangifer tarandus
Recognized subspecies: Barren-ground Caribou or American Tundra Reindeer, R. t. groenlandicus; Alaskan Barren-ground Caribou or Grant’s Caribou, R. t. granti; American Woodland Caribou or Woodland Caribou, R. t. caribou; Peary Caribou or Peary Reindeer, R. t. pearyi
Family: Cervidae
Order: Artiodactyla

General Description:

• Height: males are 87-120 cm, and females are 96-112 cm, at shoulder height (Barren-ground Caribou).
• Weight: range from 110 kg (Peary Caribou) to 169 kg (Barren-ground Caribou) to 270 kg (Woodland Caribou), on average; females weigh 10-50% less than males.
• Length: males are 160-210 cm and females are 137-186 cm (Barren-ground Caribou).
• Fawns at birth are approximately 600 mm in length, and 510 mm at shoulder height.
• The pelage may be various shades of brown, depending on the subspecies; Woodland Caribou are the darkest of the subspecies, Barren-ground Caribou are intermediate in colour, and Peary Caribou are the lightest.
• The pelage lighter in colour along the neck, belly, and rump.
• Legs are dark with prominent white “socks.”
• A strip along the flank may or may not be visible.
• The summer coat is dark and sleek; mature males are often the first to develop their summer coat, and maternal females are the last.
• The winter coat is long with white-tipped guard hairs.
• Males develop conspicuous white manes prior to the rut.
• Dental formula: I (0/3), C (1/1), P (3/3), M (3/3).
• The hooves are wide and crescent in shape, with large dew claws and hairs that grow between the hooves, covering the pads in preparation for winter; characteristics that have adapted for snow covered and boggy habitats.
• Antlers are possessed by both males and females; although males are larger and more extravagant, and females may only possess a single antler or none at all.
• The main beam of the antlers begins at the brow, extending posterior over the shoulders and bowing so that the tips point forwards.
• Prominent, palmate brow tines extend forward, over the face.
• Males cast their antlers in late fall or early winter, after the rut.
• Females often retain their antlers until just prior to calving, possibly serving as a source of calcium during the winter.
• Males begin antlerogenesis in March; pregnant females begin regrowth in May or June.
• Developing antlers are covered in velvet until the bone has hardened; both Woodland and Barren-ground Caribou have dark brown velvet, where as other species have grey velvet.
• The annual cycle of antler development and shedding is dependent on age, sex, and reproductive status.

North American Distribution:

• All four of the above subspecies of Caribou are found within Canada, located throughout the Rocky Mountains and boreal forest, north through the Northwest Territories to the bordering shores of Greenland.
• Woodland Caribou are the most common species found within Alberta, inhabiting the Rocky Mountain and Boreal Forest Natural Regions; Woodland Caribou population also extend along the Canada and United States border, including Idaho, Montana, and Washington.
• Barren-ground Caribou are mainly found throughout the tundra, but some populations are known to migrate to northern portions of the prairie provinces during the winter months, including the Boreal Forest Natural Region of Alberta.

Habitat Description:

• Woodland Caribou habitats include alpine ridges and meadows, as well as mature and old subalpine forests that support abundant arboreal and/or terrestrial lichens.
• In north eastern Alberta, Woodland Caribou prefer boreal mixed-wood and fen habitats.
• Barren-ground Caribou are mostly located within muskeg and bog habitats during the winter to shrub-dominated tundra landscapes, north of the treeline for the summer.
• Pearly Caribou are found in the most arctic regions within polar “deserts” year-round.
• Snow cover is maintained within Caribou habitat for 7-9 months of the year, on average.
• Snow depth thresholds are usually between 60 and 70 cm; Woodland Caribou often endure greater snow depths during mid to late winter.

Movements and Migratory Habits:

• Caribou are gregarious, often in bands of 10-50 individuals; larger, more loosely formed herds may include nearly a thousand individuals.
• Congregations occur during three distinct times of the year: in late winter, prior to the spring migration; after the calving period; and, prior to the fall migration and annual rut.
• Barren-ground Caribou may travel over 1200 km during migration, stimulated by changes in the amount of daylight and snow pack.
• Woodland Caribou migrate in a similar manner as Barren-ground Caribou; those in mountainous habitats make vertical migrations between summer and winter home ranges.
• Many Peary Caribou only make migration-like movements during the calving period, however some do migrate seasonally for 200-500 km.
• Woodland and Barren-ground Caribou use frozen lakes and rivers as corridors during migratory periods.
• Calving is a significant factor driving migratory behaviour for both Woodland and Barren-ground Caribou.

Diet and Foraging Strategy:

• Caribou move about continuously while feeding when food is abundant.
• Caribou use an array of plant types, including grasses, sedges, forbs, arboreal and terrestrial lichens, fungi, as well as trees and shrubs.
• Lichens (i.e. fruticose and foliose lichens) are a key component of a Caribou’s fall/winter diet.
• Snow conditions tend to determine feeding habits; terrestrial lichens (Cladina spp. and Cladonia spp.) are replaced in the diet with arboreal lichens (Alectoria spp. and Bryoria spp.) as snow depth increases.
• Caribou will dig craters within the snow with their front feet to find vegetation, until the snow becomes too hard.
• Woodland Caribou populations that live in deep snowpack ecosystems are particularly dependant upon arboreal lichens during the winter months and represent a mountain ecotype, which occurs along the Rocky Mountain Trench in British Columbia.
• Barren-ground Caribou prefer fungi throughout the fall and select for the leaves of trees and shrubs, such as Salix spp. and Vaccinium spp., and grasses during the winter; browse is used as well, but to a lesser degree.
• Grasses, sedges, and forbs become more dominant within the diet as spring/summer progress; sight and smell are used to select specific parts of plants that have high nutritional value.

Reproduction:

• The rut begins in late September or early October with sparring bouts between males.
• Other rutting behaviours include pursuing females, bush gazing, bush thrashing, hock rubbing/tampling, mock battles, rearing, and flailing.
• Open habitats are preferred for rutting behaviour; Barren-ground Caribou will return to the treeline.
• Rutting behaviour varies by population.
• Woodland Caribou may gather harems of 12 to 15 females; however, they are not considered to be true breeding groups.
• Barren-ground Caribou do not gather harems.
• Copulation is brief, due to the overwhelming weight of the males.
• The gestation period is seven to eight months long.
• Pregnant females tend to return to known calving grounds, forming maternity bands, and only seeking isolation if calving occurs either early or late in relation to the peak calving period.
• Calving takes places between mid-May and the beginning of July.
• A single calf is often born; twinning is rare.
• Calves and their mothers form nursery bands within hours of calving.
• Mothers use head bobbing and vocalizations to strengthen following responses from calves.
• Males, non-pregnant females, and yearlings are permitted to rejoin the herd as summer progresses.

Conservation Status:

• Provincial Status: Woodland Caribou (At Risk); Barren Ground Caribou (Accidental/Vagrant).
• Federal Status: Boreal Woodland Caribou Population (Threatened); Southern Mountain Woodland Caribou Population (Threatened); Northern Mountain Woodland Caribou population (Special Concern).
• Potential Caribou habitat occupied most of the northern half of North America.
• Human settlement and further land use influences within the southern portion of their range caused Caribou habitat to be reduced.
• Caribou have been valued, both culturally and economically, within Canada.
• Populations decreased during the 1960s and 1970s; however, they have nearly doubled in number since the early 1990s.
• There are over 200 known herds of Caribou throughout North America today.