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

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.

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

Mark Raycroft / Woodland Caribou (Rangifer tarandus caribou) mother nursing calf, Newfoundland, Canada

Suzi Eszterhas / African Elephant (Loxodonta africana) mother and calf at waterhole, Mashatu Game Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) mother and eight-month-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) mother and four-month-old cubs, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) six-week-old cub nuzzling mother, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) mother playing with her six-week-old cub, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub playing with mother's tail, Jao Reserve, Botswana

Suzi Eszterhas / Leopard (Panthera pardus) five-week-old cub playing with mother's tail, Jao Reserve, Botswana