Eric Baccega / Female Polar bear (Ursus maritimus) grooming, with two cubs playing nearby, Wapusk National Park, Manitoba, Canada, February.

Eric Baccega / Polar bear cub 3 months (Ursus maritimus) playing in the front of the day den in march. Wapusk National Park. Churchill, Manitoba, Canada

Eric Baccega / Polar bear cub 3 months (Ursus maritimus) playing in the front of the day den in march. Wapusk National Park. Churchill, Manitoba, Canada

Eric Baccega / Polar bear (Ursus maritimus) female coming out the den with one three month cub. Wapusk National Park, Churchill, Manitoba, Canada, March.

Eric Baccega / Polar bear (Ursus maritimus) female coming out the den and shaking off snow. Wapusk National Park, Churchill, Manitoba, Canada, March.

Matthias Breiter / Polar Bear (Ursus maritimus) mother and three-month-old cubs, Wapusk National Park, Manitoba, Canada

Eric Baccega / Polar Bear (Ursus maritimus) mother with her 3-month cub, soon after emerging from their hibernation den. Wapusk National Park, Manitoba, Canada, March.

Eric Baccega / Polar Bear (Ursus maritimus) mother resting while her 3-month cubs play. Wapusk National Park, Manitoba, Canada, March.

Suzi Eszterhas / Polar Bear (Ursus maritimus) three to four month old cub peeking over mother's body while she is tranquilized by researchers, vulnerable, Wapusk National Park, Manitoba, Canada

Matthias Breiter / Polar Bear (Ursus maritimus) three month old cub looking out of its birth den, vulnerable, Wapusk National Park, Manitoba, Canada

Thomas Mangelsen / Polar Bear (Ursus maritimus) male on broken ice, Wapusk National Park, Manitoba, Canada

Thomas Mangelsen / Polar Bear (Ursus maritimus) cub with paw over eyes, nestled in mothers' chest, Wapusk National Park, Manitoba, Canada