Ingo Arndt / Red-eyed tree frog (Agalychnis callidryas) eye closed with semi-transparent eyelid that allows it to see its surroundings even while resting, Costa Rica.

Andy Rouse / African Lion (Panthera leo) female carrying young cub. Masai Mara, Kenya, Africa. August.

Edwin Giesbers / Western lowland gorilla (Gorilla gorilla gorilla) twin babies age 45 days resting on mother's chest, one suckling. captive, occurs in Central Africa. Critically endangered.

Yukihiro Fukuda / Japanese macaque (Macaca fuscata fuscata) rare white furred baby playing with another baby. Jigokudani Valley, Nagano Prefecture, Japan. June.

Staffan Widstrand / Wild Wonders of China / Crested myna starlings (Arcidotheres cristatellus) sitting on domestic waterbuffaloes (Bubalus domesticus), Poyang Ho Lake, Jiangxi province, China

Espen Bergersen / Atlantic puffins (Fratercula arctica) group interacting, Hornoya bird cliff, Finnmark, Norway. March.

Pal Hermansen / Yellow-billed oxpecker (Buphagus africanus) on African buffalo (Syncerus caffer), Masai Mara, Kenya

Ole Jorgen Liodden / Walruses (Odobenus rosmarus) adult and young hauled on ice. Hinlopen, Svalbard, Norway, June.

Ole Jorgen Liodden / Arctic tern (Sterna paridisea) mobbing, Arctic fox (Alopex lagopus) in Spitsbergen, Svalbard, Norway, July.

Solvin Zankl / Black backed jackal (Canis mesomelas) attacking Cape fur seal (Arctocephalus pusillus) pup, Sperrgebiet National Park, Namibia, December. Sequence 3/6

Steven Kazlowski / Polar bear (Ursus maritimus) young bear rolling around in the snow, on newly formed pack ice during autumn freeze up, Beaufort Sea, off Arctic coast, Alaska

Mark MacEwen / Japanese macaque (Macaca fuscata) relaxing in hot spring in Jigokudani, Yaenkoen, Nagano, Japan, February.