Adult male Polar Bear, Ursus maritimus, resting on frozen lake near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bear, Ursus maritimus, in fresh snow and spruce trees near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bear, Ursus maritimus, yawning while resting near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bear, Ursus maritimus, close-up near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bears (Ursus maritimus) in ritualistic fighting stance (injuries are rare) near Churchill, Manitoba, Canada.

Adult male Polar Bear, Ursus maritimus, (head detail) near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bears, Ursus maritimus, in ritualistic fighting (this almost never leads to serious injury) near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bear, Ursus maritimus, shaking like a dog after scratching his back on a willow tree near Churchill, northern Manitoba, Hudson Bay, Canada

Curious young male Polar Bear, Ursus maritimus, standing against Tundra Buggy near Churchill, northern Manitoba, Hudson Bay, Canada

Female Polar Bear, Ursus maritimus, on fresh snow near Churchill, northern Manitoba, Hudson Bay, Canada

Male Polar Bears, Ursus maritimus, engaged in ritualistic mock fighting (serious injuries are rare), near Churchill, northern Manitoba, Hudson Bay, Canada

Male Polar Bears, Ursus maritimus, engaged in ritualistic mock fighting (serious injuries are rare), near Churchill, northern Manitoba, Hudson Bay, Canada

Adult male Polar Bear, Ursus maritimus, on frozen lake near Churchill, northern Manitoba, Hudson Bay, Canada