Known to the Mikmaq as "Xalibou," the one who paws or shovels, gracing our 25-cent piece and being a very important economic and cultural resource for the north youd think that caribou would be more renowned in Canada.
Worldwide, there are an estimated 5 million caribou. Their domesticated cousins, the reindeer are still raised in Northern Scandinavia. Our North American counterparts most likely migrated via the Bering land bridge during the last ice age, as artifacts such as native tools fashioned from bone have been found on the Seward Peninsula.
The two main subspecies of caribou, the barren ground and the woodland, here are both called Rangifer tarandus . This week well feature the barren ground race; in the future well look at the Woodland caribou.
R tarandus is of the Order Artiodactyla, the even-toed hoofed mammals in the Family Cervidae, the deer. The barren ground caribou are somewhat smaller than the woodland subspecies and lighter in coat with smaller antlers. Adult females weigh 80-90 kg. Males in winter average 109 kg, but may weigh in at more than 140 kg during the rut. Lifespan is up to 15 years for females, 13 years for males, and one calf is born after eight months gestation and is ready to walk within minutes.
R tarandus is the most ancient evolutionarily speaking, of the deer species. One main distinction from all other deer is the females ability to grow antlers. Caribou antlers may be distinguished from those of elk by the palmate or flattened brow tine, which blocks the growth out over the snout. (Look at a quarter.)
Antlers start growing in spring from bony protuberances on the skull, being fed by the vascular dark brown soft velvet, reaching mature sizes of up to a 152 cm spread by August, when the velvet then dries and sheds off. Antlers are then shed in winter, completing the annual cycle.
Their large cloven hooves are well adapted to their environment. They act as snowshoes in muskeg, soft earth and through deep snow. They are swimming paddles and for foraging they act as shovels, allowing them to paw, or "crater" through up to 1 metre of snow to locate lichen, virtually their only winter food source. While walking, a characteristic clicking sound is caused by the ankles sesamoid bone rubbing.
The caribous fur is highly adapted to its harsh environment as well. The outer guard hairs are hollow and honeycomb structured, trapping air not only as superior insulation but also providing buoyancy, which further enhances their swimming ability. Even their stomachs are adapted to their diet, containing bacteria and protozoa specifically designed to digest lichen.
Of an estimated 1.2 million barren ground caribou in Canada today, a small number of cows and calves have been satellite radio collared to track and study movements and population dynamics. They migrate on average 2,700 km up to 5,000 km per year, being the most traveled of all land mammals. Why migrate? The main theories are to avoid insect harassment, locate food sources and escape predation during vulnerable calving season.
Continued next week.