Next to the bears, the cougar is the largest, most powerful Canadian predator. Large males can measure 2.5 m (8 ft.) in total length and may weigh more than 90 kg (200 lb.). Despite their size, cougars are extremely wary, and so are infrequently seen in their natural habitat by humans.

Cougars prey upon deer, North American elk, bighorn sheep, mountain goats, beavers, snowshoe hares and even mice. Their preference is for fresh meat, so they rarely scavenge from old kills.

Once numerous from the Atlantic to the Pacific and from northern North America to southern Argentina, habitat destruction has reduced much of its range. As a result, in Canada most cougars are found in the Rocky Mountains of British Columbia and Alberta.

Recent sightings in Nova Scotia, New Brunswick, Quebec, Ontario and the eastern United States indicate that the eastern cougar population may be making a comeback. However, the availability of prey (mainly white-tailed deer) and protection from hunting do not seem to have been important factors in helping the animal re-establish itself. The biggest obstacle to the survival of the eastern cougar may be the loss of undisturbed habitat.