Matthew Maran / Black Bear (Ursus americanus) at waters edge, Barkley Sound, Vancouver Island, British Columbia, Canada

Eric Baccega / Grizzly bear (Ursus arctos horribilis) catching salmon in Brooks river, Katmai National Park, Alaska, USA, July

Peter Cairns / naturepl.com / European brown bear (Ursus arctos) with three cubs, Finland, June

George Sanker / Young Black bear (Ursus americanus) cub climbing mature fir tree, Yellowstone National Park, Wyoming, USA, May

George Sanker / Grizzly Bear (Ursus arctos horribilis) in sage brush above meadow and trees. Grand Teton National Park, June.

Steven Kazlowski / Polar bear (Ursus maritimus) sow with her cub outside their den in late winter, Arctic coast of Alaska, USA

Steven Kazlowski / Polar bear (Ursus maritimus) sow standing with her cub outside their den in late winter, Arctic coast of Alaska

Steven Kazlowski / Polar bear (Ursus maritimus) traveling along the coast on sea ice in search of seals, Svalbard, Norway

Steven Kazlowski / Polar bear (Ursus maritimus) head close-up portrait of an adult male, with snowflakes on fur, Barter Island, 1002 area of the Arctic National Wildlife Refuge, Alaska

Steven Kazlowski / Polar bear (Ursus maritimus) sow hunting for seals amidst the sea ice floating off the coast of Svalbard, Arctic.

Steven Kazlowski / Polar bear (Ursus maritimus) portrait of a tagged and collared female in early autumn, with snow on her face. Barter Island, 1002 area of the Arctic National Wildlife Refuge, Alaska

Orsolya Haarberg / Brown bear (Ursus arctos) in woodland, Finland.