The cougars favorite food is deer. They also mainly eat elk and beavers. They can catch prey as small as deer mice and as large as moose calves. Other prey includes coyotes,rabbits, rodents, raccoon's, and on occasion, pets and livestock. Usually a cougar kills only one large animal at a time.
Their predators are humans and grizzly bears.
The cougars niche is to help with population control of deer, elk, and beavers. A niche is a job in its community.
Cougars appear to suffer from relatively few internal and external parasites.