The extreme cold, harsh soils, and limited plant communities of the Northern Arctic are reflected in the relatively low diversity and abundance of mammals. Of the approximately 200 species of mammals found in Canada, fewer than 20 occur in the ecozone. There are few insect species and a total absence of reptiles and amphibians.
This land at first may appear to be empty of life, particularly in winter. But three large mammals -- the Muskox, Caribou, and Polar Bear -- are very much at home here throughout the year.
Muskoxen are found across much of the Northwest Territories portion of the area. They roam the plains and plateaus in small bands or individually during the summer, and in larger family groups in the fall and winter. Peary Caribou, found only on the high arctic islands, are smaller and more pale than the Barren-ground Caribou which inhabit the mainland of the Northwest Territories, Baffin Island, Quebec, and Labrador. Although they lack the spectacular mass migrations of many Barren-ground Caribou herds, most Peary Caribou make seasonal movements of up to several hundred kilometres between arctic islands. Polar Bears also range widely as they journey along coastal areas or follow the sea ice in search of seals.
The only small mammal hardy enough to survive the harsh climate of this region is the Collared Lemming. It seeks protection from frigid winter temperatures under a protective blanket of snow. Lemmings are active all winter, scurrying through tunnels to their well-stocked food chambers. To the Arctic Fox, Ermine, and birds such as the Gyrfalcon and Snowy Owl, they are a vital source of food. A reduction in lemming numbers, caused by severe weather or as yet unexplained population cycles, can have a ripple effect in many arctic food chains.
In spring, the land reverberates with the sound of thousands of migrant birds. Immediately after arrival, they begin a frantic schedule of breeding, nesting, and rearing young. Snow Geese, Brant, and Canada Geese nest in moist wetlands that line coastal areas and river valleys. Eider and Oldsquaw Ducks nest beside small ponds on grassy tundra. These areas also support a surprising number of shorebirds, including the Black-bellied Plover, Ruddy Turnstone, and Red Phalarope. Hoary Redpolls, Horned Larks, and Snow Buntings need very little vegetation cover for nesting and thus can survive in even the most sparse arctic landscape.