While the George River caribou herd of Quebec is considered to be the largest in the world at 500,000 animals, the Porcupine herd of the Yukon, numbering 130,000 today is the most extensively studied and has the largest range, covering an area of 260,000 square km.
The Porcupine herd winters in the Mackenzie delta of the North West Territories. In spring, females lead the herd from the boreal forest of the Richardson and Ogilvie Mountain ranges over the continental divide, fording the Porcupine River, zigzagging through the taiga to the calving grounds. They calve up to 40,000 offspring in early June in Ivvavik National Park on the Northern tip of the Yukon, and Alaskas Arctic National Wildlife Refuge, "Americas Serengeti." This area encompasses the "1002 lands" section of the coastal plain of Alaska on the Beaufort Sea.
Fifty per cent of calves die in the first year from drowning, pneumonia, or predation by grizzlies, and wolves. The herd then spends the short summer seeking refuge from harassment by biting insects on the windswept areas of the tundra while foraging for sedges, grasses, branches of dwarf willow and birch.
Exploration and settlement of the north was made possible by the caribou herds. Not only are they a source of meat but also clothing and tools fashioned from bone and antler. The Gwichin community of Old Crow, a village situated in the middle of the migration route, has been intimately dependent on the Porcupine herd both culturally and economically for generations. This herd may consume half a billion kilograms of forage a year, while returning 2 million kilos of biomass back to the ecosystem, making this herd the major wildlife resource of the Northern Yukon.
Threats to a thriving healthy population of the barren ground caribou include the presently-on-hold proposed oil drilling in the so-called "1002 lands," the Porcupine herds calving ground. Human encroachment via road access, such as the Dempster Highway, has made the herd more accessible to hunting. Global warming and its potentially accelerated effects in the north are of great concern at this time.
A male woodland caribou weighs from 112 to 270 kg. Females are remarkably smaller, weighing in at only 67-158 kg. Not a lot is known about their movements; they are very elusive and not well understood, having been called the "shy and gentle ghost of the forest." Total population is estimated at 30,000, with many small "herds" identified distributed in pockets from northern B.C. and Alberta through the northern forests to Quebec.
With the presence of beaver in their range, these animals may have access to arboreal lichen. A true symbiotic relationship exists as the beaver fell some of these lichen-laden trees to make it more accessible. The Woodland subspecies prefers the cover of old growth boreal forest, preferably comprised of black and white spruce; tamarack and favoring mature Jack Pine. You may find them in mountainous areas as well.
Woodland caribou have different threats to their existence. They are officially regarded as a threatened species across Canada, defined as being "at risk of becoming endangered if limiting factors are not reversed." British Columbias Selkirk herd numbers only 30 animals; hardly a strong enough gene pool to sustain it. Limiting factors include predation by coyote, wolf and cougar.
Now predation is natures natural way of population control, selecting the weak and old, which keeps a population healthy. However, adding human pressures to the equation changes the whole dynamic of the system. Forestry practices of clear cutting and human activity such as fencing properties, road access to previously remote areas and snowmobiling all create additional pressure on an already delicate balance.
Forestry and farming create a fragmented landscape not suitable to woodland caribou, which require large undisturbed areas of mature conifer forest. They cannot tolerate clear-cut areas, as deer and moose may move into the area and attract more predators as well, which caribou populations are much more sensitive to. Also, deer carry a neurological parasite, harmless to them, but deadly to caribou.
There is one population of about 300-400 animals on the Slate Islands, 16sq. km on northern Lake Superior. Theoretically, they swam 8 km to escape predation and competition from the mainland. So far, they have been protected from human activity.
So you can see that Santas hoofed helpers have been around a long time, and it is our duty to see that they stick around to help future generations.
For additional information on the caribou go to www.arctic-caribou.com for detailed impact studies, or www.cariboucommons.com about the threat of industrial development in the arctic.