Laurent Geslin / African elephant young playing together{Loxodonta africana} Etosha NP, Namibia

George Sanker / Two Red fox (Vulpes vulpes) cubs playing with mother, Grand Teton National Park, Wyoming, USA, June

Pete Oxford / Two Giant Pandas (Ailuropoda melanoleuca) play fighting, Wolong China Conservation and Research Centre for the Giant Panda within Wolong Reserve, Sichuan Province, China 2006

Anup Shah / Gelada baboon (Theropithecus gelada) juvenile playing in early evening light, Simien Mountains National Park, Ethiopia, November

Wild Wonders of Europe / Widstrand / Two Eurasian brown bear (Ursus arctos) cubs fighting, Suomussalmi, Finland, July 2008

Steven Kazlowski / Pair of Arctic foxes (Vulpes / Alopex lagopus) one adult in its winter coat and one pup in its summer coat, play vigorously on the pack ice, 1002 area of the Arctic National Wildlife Refuge, Alaska, O...

Inaki Relanzon / Two Polar bears (Ursus maritimus) play fighting, Churchill, Hudson Bay, Canada. October

Peter Blackwell / Topi calves play fighting, Masai Mara, Kenya

Christophe Courteau / Two African lion cubs (Panthera leo) playing on a road in the Kalahari Desert, Botswana.

Bryan and Cherry Alexander / Emperor penguin (Aptenodytes forsteri) chicks playing with a piece of ice as they wait for their next meal. Snow Hill Island, Antarctica, October.

Claudio Contreras / Guadalupe fur seal (Arctocephalus townsendi) pup playing with kelp stem in coastal waters, Guadalupe Island Biosphere Reserve, off the coast of Baja California, Mexico, March

Edwin Giesbers / Hippopotamus (Hippopotamus amphibius) rolling on back playing in water, Tanzania

Anup Shah / Playful young Sumatran Orang utan under leaf shelter {Pongo abelii} Gunung Leuser NP, Sumatra, Indonesia

Anup Shah / Young Chimpanzee hanging upside down in tree {Pan troglodytes schweinfurtheii} Gombe NP, Tanzania. 2002

Yukihiro Fukuda / Japanese macaque (Macaca fuscata) juveniles playing at the top of a tree, Shodoshima, Japan

Anup Shah / Juvenile orang utan (Pongo abelii) swinging upside down from liana, Gunung Leuser NP, Sumatra, Indonesia

Mary McDonald / Two young Olive baboons {Papio anubis} playing with each other in the Upper Masai Mara GR, Kenya

Anup Shah / African lion {Panthera leo} young cub, two months old, playing with mother's tail, Masai Mara GR, Kenya

Anup Shah / African lion (Panthera leo) adolescents play fighting, Masai Mara National Reserve, Kenya. April.

Anup Shah / Lion cubs playing Masai Mara Kenya

Anup Shah / African lion {Panthera leo} cub playing with sleeping lioness' ear, Masai Mara GR, Kenya

Anup Shah / Cheetah cubs playing near mother {Acinonyx jubatus} Masai Mara, Kenya

Edwin Giesbers / Two Lynx (Lynx lynx) cubs playing, captive

Philippe Clement / Wild cat (Felis silvestris) two kittens playing on tree trunk in forest, Germany. Captive

Fabrice Cahez / Red fox (Vulpes vulpes) cubs playing in grass, Vosges, France, April

Ann & Steve Toon / Cape fox cubs (Vulpes chama) play-fighting, Kgalagadi Transfrontier Park, Northern Cape, South Africa

George Sanker / Black bear (Ursus americanus) cubs, male and female, one black the other brown, playing roughly, Yellowstone National Park, Wyoming, USA, May

Wild Wonders of Europe / Widstrand / Eurasian brown bear (Ursus arctos) cubs fighting while playing, Suomussalmi, Finland, July 2008

Staffan Widstrand / Polar bear lying on back playing with twig {Ursus maritimus} Canada Churchill,

Anup Shah / Rock hyrax with young climbing on back {Procavia capensis} Serengeti NP, Tanzania, East Africa

Andy Rouse / Two European Rabbit (Oryctolagus cuniculus) young playing and jumping. UK, August.

Andy Rouse / Two European Rabbit (Oryctolagus cuniculus) young playing, leaping in air. UK, August.

Bernard Castelein / Himalayan Marmots (Marmota himalayana) play-fighting, Ladakh, India

Anup Shah / Young African elephants with trunks entwined, Masai Mara, Kenya

Charlie Summers / Juvenile Rocky Mountain Goats (Oreamnos americanus) playing on the top of a rocky outcrop. Rocky Mountain national Park, Colorado, USA

Anup Shah / African elephant infants (Loxodonta africana) play fighting. Masai Mara Nationa Reserve, Kenya. February

Suzi Eszterhas / Bat-eared fox {Otocyon megalotis} 7-months pups playing, Masai Mara Triangle, Kenya

Andy Rouse / European red fox (Vulpes vulpes) cubs playing outside earth, UK (non-ex)

Nick Garbutt / Two Antarctic Fur Seals (Arctocephalus gazella) pups playing in surf. Gold Harbour, South Georgia, South Atlantic.

Doug Perrine / Atlantic spotted dolphins in mock combat {Stenella frontalis} Bahamas, Caribbean ~(Non-ex).

Jeff Rotman / Large group of Californian sealions (Zalophus californianus) swimming and playing underwater, Anacapa Island, California, Pacific Ocean

Eric Baccega / Young Orang-utans playing (Pongo pygmaeus) holding hands ,native to Borneo, captive.

Anup Shah / Three young Eastern common chimpanzees{Pan troglodytes schweinfurtheii} hanging from branch. Mahale NP, Tanzania.

Anup Shah / Two Chimpanzee juveniles playing in tree (Pan troglodytes) orphans at Sweetwater Sanctuary, Kenya, Africa

Anup Shah / Two Gelada baboon (Theropithecus gelada) juveniles playing, Simien Mountains National Park, Ethiopia, November

Anup Shah / Gelada baboon (Theropithecus gelada) juveniles play fighting, Simien Mountains National Park, Ethiopia, November

Anup Shah / Olive baboon juveniles (Papio cynocephalus anubis) playing together, Masai Mara National Reserve, Kenya. March.

Anup Shah / Olive baboon(Papio cynocephalus anubis) baby aged 3-6 months playing in a fallen tree, Masai Mara National Reserve, Kenya. March.

Anup Shah / African lion (Panthera leo) cub aged 1-2 years play fighting with a lioness, Masai Mara National Reserve, Kenya. March.

Anup Shah / Cheetahs cubs play fighting {Acinonyx jubatus} Masai Mara, Kenya

Anup Shah / African lion {Panthera leo} young cub, two months old, playing on lioness, Masai Mara GR, Kenya

Anup Shah / African lion {Panthera leo} rear view of young cub looking over the back of lioness, Masai Mara GR, Kenya