The Northern Lynx, (Lynx Lynx), also known as the Eurasian Lynx, is the medium-sized cat of the northern forests. It has a stocky body with big, broad paws, long, powerful legs, a very short, black-tipped tail and tufted ears. The tail has probably been shortened as a protection against the extreme cold that this lynx must often face during the long northern winters. But what the animal loses in conspicuous tail-signals, it makes up for with movements of its tufted ears and its remarkable neck-ruff. The Northern Lynx is driven by its harsh environment to eat anything it can catch, but it specializes in rabbits and hares, which make up most of its diet, along with occasional small deer, chipmunks, rats, mice and lemmings. Because of the scarcity of food, each individual covers a large territory, sometimes as vast as 300 sq km (over 100 sq miles).

The New World counterpart of the Northern Lynx, the Canadian Lynx (Lynx canadensis), is thought by some authorities to belong to the same species. Others, however, have pointed out that the Canadian Lynx is only about half the size of the Eurasian form, lacks the spotting on the body, and has an even shorter tail. As a result, the two lynxes are now generally considered to be two separate species.

The Canadian Lynx is a cold-country cat with a stocky body, very thick, dense fur, long legs with enormous, 'snow-shoe' paws, and like the Northern Lynx, black-tufted ears. Its coat is usually plain, but sometimes a faint spotting is visible. There is a black and white throat ruff that fans outwards when the cat hisses.

A solitary hunter, with individual territories of up to 250 sq km (100 sq miles), the Canadian Lynx feeds almost entirely on Snowshoe Hares, but will occasionally eat mice, voles, squirrels and some ground birds.