Steven Kazlowski / Grizzly bear (Ursus arctos horribilis) young rare blonde (white) bear plays with a young dark coloured bear along the coast of Katmai National Park, Alaskan peninsula, USA

Edwin Giesbers / Two Kodiak / Alaskan brown bears (Ursus arctos middendorffi) close up, fighting, captive.

Eric Baccega / Female Kodiak brown bear (Ursus arctos middendorffi) fighting male to protect her cubs, Kodiak Island, Alaska, USA, July

Matthias Breiter / Kodiak Bear (Ursus arctos middendorffi) with mouth agape, native to Kodiak Island, Alaska

Matthias Breiter / Kodiak Bear (Ursus arctos middendorffi) four week old cub, native to Kodiak Island, Alaska

Steven Kazlowski / Grizzly bear (Ursus arctos horribilis) young rare blonde (white) bear plays with a young dark coloured bear along the coast of Katmai National Park, Alaskan peninsula, USA

Steven Kazlowski / Grizzly bear (Ursus arctos horribils) sow sits in riverbed with a mountain range in background, east coast of Katmai National Park on the Alaskan peninsula, USA

Loic Poidevin / Juvenile Kodiak bear (Ursus arctos mindendorfi) playing with plant, Kodiak Island, Alaska, USA, July

Loic Poidevin / Three Kodiak bears (Ursus arctos mindendorfi) female and two young sitting on pier, Kodiak Island, Alaska, USA, July

Loic Poidevin / Kodiak bear (Ursus arctos mindendorfi) portrait, in rain, Kodiak Island, Alaska, USA, July

Edwin Giesbers / Two Kodiak / Alaskan brown bears (Ursus arctos middendorffi) head portrait in water, with paw resting against tree limb, captive.

Edwin Giesbers / Two Kodiak / Alaskan brown bears (Ursus arctos middendorffi) head portrait swimming, with head above the surface of the water, captive.