Mountain caribou, an ecotype of woodland caribou (Rangifer tarandus caribou), are unique to the Inland Temperate Rainforest and Columbia Mountains of British Columbia and northern Washington and Idaho in the US. Mountain caribou are the southernmost caribou in the world. Other kinds of caribou include the barren-ground caribou of Canada’s far north, and several kinds of reindeer in Europe and Asia.
In early winter before high-elevation snows solidify, mountain caribou are found in low-elevation old-growth cedar and hemlock forests, where 1,000-year-old trees are not uncommon. Here, they feed on ground plants such as falsebox, willow, sedges, and ground lichens. In winter they subsist on arboreal lichens.
Once the mid-winter snow buries those foods, caribou move higher into subalpine spruce/fir forests. Their dinner-plate-sized feet act like snowshoes, allowing them to use the deep winter snow as a platform to reach lichens draped from old-growth trees. Arboreal lichens are their primary food in winter.
Arboreal lichens are found in abundance only in old-growth forests. Older forests also offer protection from predators.
- Caribou survived the Pleistocene Ice Age extinctions that erased mammoths, mastodons, short-faced bears, ice-age camels, and many others after making their way to North America over the Bering Land Bridge thousands of years ago.
- The declining mountain caribou populations of Canada’s southern Rockies are a more distinct breed than scientists previously believed.
- Mountain caribou are larger than deer and smaller than elk, with males weighing approximately 175 kg. Their hollow fur insulates them through the long mountain winters. Caribou are unique in the deer family in that both females and males grow antlers.
- Unique behavior allows mountain caribou to live where other ungulates cannot survive.
Mountain caribou are one of the most endangered mammals in North America. A recent census found fewer caribou than thought, with only 1600 remaining of what was once many thousands.
Globally, caribou are now under assault from a variety of human-caused threats, with climate change and tar sands oil mining in the Canadian boreal being the latest. Mountain caribou have adapted to a harsh environment in ways that no other animal can. They are resilient but not invulnerable. They need our help to survive.