Next to the bears, the cougar is the largest, most powerful Canadian predator. Large males can measure 2.3 m (8 ft.) in total length and may weigh more than 90 kg (200 lb.). They can reach a shoulder height of up to 79 cm (31 in.). Adult males are about 50% heavier and 20% longer than females. 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 kills that are more than a few days old.

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 more inaccessible mountainous regions of British Columbia and Alberta.

Despite recurring sightings of cougars in eastern North America, there is little evidence of a native cougar population in that part of the continent. The sparse genetic data from these animals suggest that most, if not all, are escaped or intentionally released captives or their offspring. Cougars appear to be moving back into parts of their historical range, particularly in Manitoba, Alberta and the Dakotas and they are extending the northern limit of their range in some regions.