Suzi Eszterhas / Brown Bear (Ursus arctos) mother and 3-4 month cubs foraging for clams. Katmai National Park, Alaska, USA, June.

Andy Rouse / Grizzly bear (Ursus arctos horribilis) cub waking up, Katmai National Park, Alaska, USA, August 2010.

Oliver Scholey / Grizzly bear (Ursus arctos horribilis) female with cub riding on back, Katmai National Park, Alaska, USA, August.

Oliver Scholey / Grizzly bear (Ursus arctos horribilis) Katmai National Park, Alaska, USA, August.

Denis-Huot,Denis-Huot / Grizzly bears (Ursus arctos horribilis) looking for salmon, Brooks river, Katmai national park, Alaska, North America,

Matthias Breiter / Sockeye Salmon (Oncorhynchus nerka) group jumping up waterfall, Brooks Falls, Katmai National Park, 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

Loic Poidevin / Grizzly bear (Ursus arctos horribilis) attempting to catch salmon leaping up rapids, Katmai National Park, Alaska, USA

Loic Poidevin / Salmon landing on head of Grizzly bear (Ursus arctos horribilis) as it is leaping up rapids, Katmai National Park, Alaska, USA

Loic Poidevin / Grizzly bear (Ursus arctos horribilis) salmon fishing in river rapids, Katmai National Park, Alaska, USA

Loic Poidevin / Grizzly bear (Ursus arctos horribilis) salmon fishing in river rapids, Katmai National Park, Alaska, USA

Mary McDonald / Grizzly Bear (Ursus arctos horribilis) male in water. Coastal Katmai National Park, southwest Alaska, USA, August.