Edwin Giesbers / Female Orang Utan (Pongo pygmaeus) sitting, holding two young. One is her own offspring, the other was rejected by its birth mother, and so this female has adopted it. Both young are 3 months old.Capt...

Danny Green / Polar bear (Ursus maritimus) female and cubs, one cub walking up slope of ice in foreground. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus), two cubs playing, leaping across sea ice, reflected in water. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus), two cubs walking on sea ice. Svalbard, Norway, July.

Oscar Dewhurst / Mute swan (Cygnus olor), two cygnets sheltering under parent's wing. Richmond Park, London, England, UK. April.

Oscar Dewhurst / Mute swan (Cygnus olor) swimming with cygnets in misty lake in morning light. Richmond Park, London, England, UK. May.

Felis Images / Asiatic lion (Panthera leo persica), female and cubs in morning light, cub biting mother's leg. Gir National Park, Gujarat, India. Photo Phillip Ross/Felis Images

Jack Dykinga / Burrowing owl (Athene cunicularia) female and ten chicks aged a few weeks. Marana, Arizona, USA. May.

Tony Heald / Elephant (Loxodonta africana) babies playing, Etosha National Park,Namibia.

Andy Rouse / Bengal Tiger (Panthera tigris) family drinking from pool, Ranthambhore, India

Five Films / Female Grey seal (Halichoerus grypus) defending pup on beach, chasing male away, Horsey, Norfolk, November.

Luke Massey / Wild boar (Sus scrofa) piglets suckling from mother, Forest of Dean, Gloucestershire, England, UK, May.