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

Kevin Schafer / Galapagos Sea Lion (Zalophus wollebaeki) pups playing, Espanola Island, Galapagos Islands, Ecuador

Donald M. Jones / Dall's Sheep (Ovis dalli) rams, Denali National Park, Alaska

Lisa Hoffner / A baby orphan Elephant (Loxodonta africana) leaning against the rump of its friend. David Sheldrick Wildlife Trust Nairobi Elephant Nursery, Kenya, August 2010.

Jan Vermeer / Emperor Penguin (Aptenodytes forsteri) chick pair, Snow Hill Island, Antarctica

Konrad Wothe / Black-tailed Prairie Dog (Cynomys ludovicianus) pair interacting, North America

Christian Ziegler / Red-eyed Tree Frog (Agalychnis callidryas) three males sitting on a stem, Soberania National Park, Panama

Konrad Wothe / Raccoon (Procyon lotor) young peering out from hole in tree, North America

Mark Raycroft / Australian Terrier (Canis familiaris) pair sitting on bench

Mark Raycroft / Black Labrador Retriever (Canis familiaris) pair sitting near autumn leaves

Mark Raycroft / Rhodesian Ridgeback (Canis familiaris) puppy pair sitting amid apples

Mark Raycroft / Australian Shepherd (Canis familiaris) puppies on hay bale

Mark Raycroft / Australian Shepherd (Canis familiaris) two puppies sitting in grass

Mark Raycroft / Australian Shepherd (Canis familiaris) puppy meeting sheep

Mark Raycroft / Two Golden Retriever (Canis familiaris) female and male adults sitting side by side

Mark Raycroft / Golden Retriever (Canis familiaris) relaxing on lawn with a young girl

Mark Raycroft / Golden Retriever (Canis familiaris) three adults

Mark Raycroft / Golden Retriever (Canis familiaris) puppies together with front paws up on a log

Mark Jones / Marine Iguana (Amblyrhynchus cristatus) pair resting after morning feeding, vulnerable, Punta Suarez, Hood Island, Galapagos Islands, Ecuador

Mitsuaki Iwago / Western Grey Kangaroo (Macropus fuliginosus) group with one scratching companion, Kangaroo Island, Australia

Fred Bavendam / Goby (Amblyeleotris sp) keeping watch while a Snapping Shrimp (Alpheus randalli) excavates their shared burrow, Bali, Indonesia

Flip de Nooyer / Gentoo Penguin (Pygoscelis papua) two downy chicks standing together in nesting colony, Antarctica

Richard Du Toit / African Wild Dog (Lycaon pictus) pair playing, Chobe National Park, Botswana

Richard Du Toit / African Wild Dog (Lycaon pictus) pair playing, Chobe National Park, Botswana

ZSSD / Asian Elephant (Elephas maximus) pair with entwined trunks, native to India, Asia, Thailand and Laos

Tui De Roy / Erect-crested Penguin (Eudyptes sciateri) pair, Antipodes Island, New Zealand

Tim Fitzharris / African Lion (Panthera leo) cubs, Hwange National Park, Zimbabwe

Gerry Ellis / African Lion (Panthera leo) two cubs playing, Serengeti National Park, Tanzania

Gerry Ellis / African Elephant (Loxodonta africana) bulls engaged in greeting ritual, Amboseli National Park, Kenya

Mitsuaki Iwago / African Lion (Panthera leo) females grooming, Serengeti National Park, Tanzania

Matthias Breiter / Grizzly Bear (Ursus arctos horribilis) cubs silhouetted against water at sunrise, Katmai National Park, Alaska

Yva Momatiuk & John Eastcott / Grizzly Bear (Ursus arctos horribilis) pair of spring cubs, Denali National Park and Preserve, Alaska

Konrad Wothe / Orangutan (Pongo pygmaeus) orphans embracing, Borneo, Malaysia

Konrad Wothe / Royal Penguin (Eudyptes schlegeli) pair, Macquarie Island, Australia

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) young bachelor stallions sniffing each other, Pryor Mountain Wild Horse Range, Montana

Konrad Wothe / Red-eared Slider (Trachemys scripta elegans) turtle, pair in pond, City Park, Munich, Germany

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) pair of spring foals, Wyoming

Heidi & Hans-Juergen Koch / Colubrid Snake (Elaphe sp) two making initial contact, using tongue (Nasovomeral sense) to identify friend, enemy, or prey

Michio Hoshino / Polar Bear (Ursus maritimus) pair loafing, Churchill, Manitoba, Canada

Mitsuaki Iwago / Koala (Phascolarctos cinereus) group in a line, Australia

Mitsuaki Iwago / Koala (Phascolarctos cinereus) on another's back, Australia

Mitsuaki Iwago / Koala (Phascolarctos cinereus) trio in a line, Australia

Mitsuaki Iwago / Koala (Phascolarctos cinereus) in a line on ground, Australia

Flip Nicklin / Bottlenose Dolphin (Tursiops truncatus) pair, Hawaii

Norbert Wu / Sam and Ange walking each other, Golden and Yellow Labrador Retriever (Canis familiaris) mix, Carmel, California

Shin Yoshino / Japanese Macaque (Macaca fuscata) pair resting in hot spring, Japan

Carol Walker / Wild horse / mustang called Mica, rounded up from Adobe Town Herd Management Area in Wyoming and adopted by photographer Carol Walker (pictured). Attending a trial obstacle clinic, designed to increas...

Carol Walker / Wild horse / mustang called Mica, rounded up from Adobe Town Herd Management Area in Wyoming and adopted by photographer Carol Walker (pictured). Attending a trial obstacle clinic, designed to increas...

Juergen Freund / Spectacled flying fox (Pteropus conspicillatus) baby swaddled in cloth ready to sleep, being hand fed from syringe by volunteer wildlife carer wearing a Flying Fox Friend T-shirt, Tolga Bat Hospital,...

Richard Du Toit / African Lion (Panthera leo) males, Kgalagadi Transfrontier Park, South Africa

Donald M. Jones / Dall's Sheep (Ovis dalli) rams, Denali National Park, Alaska

Donald M. Jones / American Bison (Bison bison) calves nuzzling, National Bison Range, Moise, Montana

ZSSD / Klipspringer (Oreotragus oreotragus) and Rock Hyrax (Procavia capensis) interacting, native to Africa

Mitsuaki Iwago / Orangutan (Pongo pygmaeus) babies interacting, Borneo, Malaysia

Aflo / ic-04501 Child sharing icecream with Spaniel puppy.

Aflo / ic-04408 Child playing with Golden retriever.

Aflo / ic-04407 Child playing opticians with Golden retriever wearing glasses.

Aflo / ic-04406 Child nose to nose with Golden retriever puppy.

Aflo / ic-04405 Child playing with puppies in toy truck.

Aflo / ic-04508 Rear view of Child looking out to sea with arm round Red setter.

Aflo / ic-04506 Person talking to dog.

Aflo / ic-04505 Child cuddling puppy in toy wagon.

Aflo / ic-04503 Collie dog and person running after ball on beach.

Aflo / ic-04502 Couple with Golden retriever looking out to sea.

Aflo / ic-04404 Child taking Golden retriever puppy for walk.

Aflo / ic-04403 Child next to large dog.

Aflo / ic-04402 Affectionate puppy licking child's ear.

ZSSD / African Elephant (Loxodonta africana) calves playing, native to Africa

Pete Oxford / King Penguin (Aptenodytes patagonicus) trio on beach, Volunteer Point, East Falkland Island, Falkland Islands

Suzi Eszterhas / Sea Otter (Enhydra lutris) pair, Monterey Bay, California

Fred Bavendam / Metallic Shrimp-goby (Amblyeleotris latifasciata) keeps watch while its Snapping Shrimp (Alpheus sp) partner works on their burrow, Bali, Indonesia

Donald M. Jones / Bighorn Sheep (Ovis canadensis) rams interacting, western Montana

Hiroya Minakuchi / Spotted Anemone Crab (Neopetrolisthes maculatus) and Anemonefish (Amphiprion sp) in sea anemone host tentacles, Celebes Sea

Yva Momatiuk & John Eastcott / Southern Elephant Seal (Mirounga leonina) pups, fat and docile weaners stay together for company and reassurance, St. Andrews Bay, South Georgia Island

Yva Momatiuk & John Eastcott / Southern Elephant Seal (Mirounga leonina) pups, fat and docile weaners stay together for company and reassurance, St. Andrews Bay, South Georgia Island

Yva Momatiuk & John Eastcott / Southern Elephant Seal (Mirounga leonina) pups, fat and docile weaners stay together for company and reassurance, St. Andrews Bay, South Georgia Island

Yva Momatiuk & John Eastcott / Gentoo Penguin (Pygoscelis papua) pair coming out of sea, Cooper Bay, South Georgia Island

Jan Vermeer / Emperor Penguin (Aptenodytes forsteri) pair, Snow Hill Island, Antarctica

Jan Vermeer / Emperor Penguin (Aptenodytes forsteri) chick pair interacting, Snow Hill Island, Antarctica

Winfried Wisniewski / Brown Bear (Ursus arctos) juveniles, Finland

Winfried Wisniewski / Brown Bear (Ursus arctos) mother with cub, Finland

Winfried Wisniewski / Brown Bear (Ursus arctos) mother and cub playing, Finland

Winfried Wisniewski / Brown Bear (Ursus arctos) cubs, Finland

Winfried Wisniewski / Brown Bear (Ursus arctos) juveniles playing, Finland

Gerry Ellis / Masai Giraffe (Giraffa tippelskirchi) juvenile males neck sparring, Masai Mara, Kenya

Gerry Ellis / Chimpanzee (Pan troglodytes) grooming another individual, Gombe Stream National Park, Tanzania

Konrad Wothe / Royal Penguin (Eudyptes schlegeli) pair, Macquarie Island, Australia

Suzi Eszterhas / Northern Elephant Seal (Mirounga angustirostris) juvenile male pair sparring, Point Piedras Blancas, California

Tom Vezo / Brown Pelican (Pelecanus occidentalis) pair interacting, California

Ingo Arndt / Northern Elephant Seal (Mirounga angustirostris) pair of females sleeping, California

Ingo Arndt / Northern Elephant Seal (Mirounga angustirostris) pair of females sleeping, California

Ingo Arndt / Guanaco (Lama guanicoe) two juveniles, Torres Del Paine National Park, Chile

Ingo Arndt / Alpine Marmot (Marmota marmota) pair peering over a rock, Hohe Tauern National Park, Austria

Ingo Arndt / Gelada Baboon (Theropithecus gelada) adult males, grooming, Simien Mountain National Park, Ethiopia

Ingo Arndt / Marine Iguana (Amblyrhynchus cristatus) pair, Santa Cruz Island, Galapagos Islands, Ecuador

Ingo Arndt / Ring-tailed Lemur (Lemur catta) pair, Madagascar