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

Winfried Wisniewski / African Lion (Panthera leo) males nuzzling, Masai Mara, Kenya

Donald M. Jones / Black-tailed Prairie Dog (Cynomys ludovicianus) pair greeting, South Dakota

Donald M. Jones / Black-tailed Prairie Dog (Cynomys ludovicianus) pair greeting, South Dakota

Richard Du Toit / Burchell's Zebra (Equus burchellii) trio nuzzling, Itala Game Reserve, South Africa

Frederique Olivier / Southern rockhopper penguin (Eudyptes chrysocome) at nest in breeding colony, stretching and knocking chick over, New Island, Falkland Islands.

Frederique Olivier / Pair of Black browed albatrosses (Thalassarche melanophris) display bonding, touching beaks, New Island, Falkland Islands.

Peter Bassett / Male Southern elephant seal (Mirounga leonina) shifting position on a beach, surrounded by females, almost crushing a pup, Gold Harbour, South Georgia.Gold Harbour, South Georgia.

Christophe Courteau / Male BurchellÕs zebra (Equus quagga burchellii) pulling the head of a dead pregnant female that died due to complications whilst giving birth, trying to wake her up, Etosha National Park, Namibia. Par...

Nate Chappell/ BIA / Belding's Ground Squirrel (Spermophilus beldingi) young playing, Oregon

Richard Du Toit / Burchell's Zebra (Equus burchellii) pair nuzzling, Rietvlei Nature Reserve, South Africa

Andy Rouse / African Elephant (Loxodonta africana) mother and calf in rain, wallowing in mud. Maasai Mara, Kenya, Africa. September.