Woodland Caribou
Rangifer tarandus caribou

Boreal Caribou Conservation in the NWT
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Biologists from Environment and Natural Resources will be discussing boreal caribou at community and comanagement meetings throughout the NWT. We want to hear from you so please attend and make your opinions heard. Please tell us what you think is important for boreal caribou management.

Background and Description

There are several subspecies of caribou in the NWT, of which woodland caribou are the largest. Male woodland caribou in the NWT weigh an average of 150kg and can reach 1.2 m high at the shoulder. Their brown summer coat turns greyish in winter. In all seasons their neck, mane, underbelly, rump and a patch above each hoof is a creamy white.  Caribou are the only members of the deer family (Cervidae) in which both males and females grow antlers.  Males have massive antlers while those of females are much smaller. Generally, antlers of woodland caribou are thicker and broader compared to those of barren-ground caribou.  Woodland caribou tend to spend the entire year within the forest rather than making the long migration across the tundra each year the way barren-ground caribou do.  Woodland caribou are also well adapted to their northern environment.  Like all caribou, their large, well-insulated hooves prevent sinking when traveling on wetlands and snow and are adapted for digging through snow for food.     Photo by R. Popko, ENR

In Canada, woodland caribou have been divided into five distinct populations depending on where and how they live: Boreal, Northern Mountain, Southern Mountain, Atlantic-Gaspésie and Newfoundland populations.  The NWT is in the range of two of these populations, the Boreal population and the Northern Mountain population.

The Northern Mountain caribou herds in the NWT include the Redstone, South Nahanni and Bonnet Plume herds and possibly some others.  Northern Mountain caribou occur in groups that may number in the thousands during late summer to late spring and have distinct seasonal migrations, including use of different elevations during the changing seasons.  Boreal caribou are similar to the Northern Mountain caribou that live in the Mackenzie Mountains but have a different lifestyle.  Boreal caribou live in the forests east of the Mackenzie Mountains, tend to live in small groups, prefer to stay within the forest most of the year, and do not migrate.

Population Size and Trends

There is little information about historical populations of woodland caribou. In 1982, the woodland caribou population in Canada was estimated at 193 000 animals. Since then, there has been a downward trend in almost all populations across Canada.  In the NWT, the Boreal population of woodland caribou was estimated between 4000 and 6400 in 2001.  The Northern Mountain population in the NWT is shared with, and counted by, the Yukon, which has estimates up to 48 000 in 2001; the portion occurring in the NWT is unknown.

Habitat

Woodland caribou generally prefer mature or old growth coniferous forests associated with bogs, lakes, and rivers. These forests offer high concentrations of ground and tree lichens. In winter, woodland caribou tend to favour uplands, bogs and south facing slopes where the snow is not too deep. Their winter diet consists of up to 80 per cent ground and tree lichens. In summer, they prefer areas such as forest edges, marshes and meadows that provide the fresh green growth of flowering plants and grasses. Calving grounds are vital to the well being of all caribou populations. Some of the best-known woodland caribou calving areas in the NWT are islands off the northwest shore of Great Slave Lake, since these areas are relatively isolated and predator-free. Females migrate to these islands when there is still ice on the lake and swim back to shore a few weeks after calving.

Woodland caribou can live to be 15 years old. Most females begin breeding at 28 months. Males can breed as early as 18 to 20 months, but competition usually prevents them from breeding until their third or fourth year. In some populations, depending on the ratio of males to females, males form harems of 12-15 females. The breeding season, or rut, is usually in late September or early October. During the rut, males use their antlers in clashes to determine dominance. A single calf is usually born in May or early to mid-June.

Woodland caribou in the NWT are at the northern extent of their range.  Wildlife species expanding their range northwards could bring unknown diseases or parasites to woodland caribou; however, effect of diseases, parasites, and insect harassment is currently unknown for woodland caribou.  Over the past 10 years, heavy truck traffic has increased on NWT highways, including winter roads that might increase the number of deaths and injuries to caribou by collisions with vehicles. 

We can also look at what has happened and is happening to woodland caribou in other parts of Canada to give us some idea of the current and potential threats to these caribou populations in the NWT.  In Alberta, agriculture, timber harvesting and especially oil and gas development have resulted in vast habitat changes and loss of the northern boreal forest.  These activities require trees to be removed, new roads built, and seismic lines and pipeline right-of-ways to be cleared.  Also woodland caribou, particularly the Boreal population, using areas near roads and seismic lines are more vulnerable to harvest and predation.  All of these types of activities are expected to increase in the NWT.  Woodland caribou have always co-existed with predators.  But cleared areas, especially long clearings like roads and seismic lines, make it easier for wolves and bears to travel through the forest and locate prey.  Food attractants like commercial waste fish piles and remote garbage dumps may increase the number of predators in some areas and increase the risk of predators finding caribou. 

Outside the NWT, declining numbers and habitat loss has meant that woodland caribou are no longer found in some areas where they used to live.  COSEWIC designated the Boreal population of woodland caribou as Threatened in May 2000 and of Special Concern for the Northern Mountain population in May 2002.  This concern about Boreal and Northern Mountain caribou in much of Canada also led to Boreal caribou listed as Threatened and Northern Mountain listed as Special Concern under the federal Species at Risk Act in 2004.  Boreal caribou are now protected on federal lands and a national Recovery Strategy is being developed to conserve and recover boreal caribou populations and their habitat across Canada.

In the NWT, a quota system helps protect woodland caribou from over-harvesting by non-Aboriginal people.  The NWT has a harvest limit of one woodland caribou per year (either Boreal or Northern Mountain, but not both) for resident hunters; non-residents can only hunt woodland caribou in the Mackenzie Mountains.  There is no limit or closed season for boreal caribou for Aboriginal hunters.  We think the total woodland caribou harvest is low, but we don’t collect harvest information from all hunters so we cannot be certain.

Recovery

Under the national Recovery Strategy, the Department of Environment and Natural Resources is developing an Action Plan for the conservation of Boreal caribou in the NWT.  The first step in developing an Action Plan for conserving Boreal caribou is to understand the NWT Boreal caribou population.  Because they live in small groups, Boreal caribou are difficult to count so we don’t know how many animals there are.  Although Aboriginal hunters have lived with Boreal caribou for generations, scientific studies in the NWT only started in 2001.  So far, hunters have been interviewed in the Inuvialuit, Gwich’in, and Sahtu regions to find out where boreal caribou have been seen in the past.  Dehcho First Nations have provided information on Boreal caribou harvesting and observations and similar work is planned for Wek’èezhìi.  Biologists have also put radio collars on Boreal caribou in the Inuvialuit, Dehcho, Sahtu, and South Slave regions to collect information on where the animals go, what kind of habitat they use, and how the population is changing.  This information will help identify what steps might be needed to help manage the current and potential threats to Boreal caribou.

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       Site last updated Tuesday, February 19, 2008