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.

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

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

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

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

Cyril Ruoso / Ring-tailed Lemur (Lemur catta) mother with young drinking, Anja Park, Madagascar

Flip Nicklin / Humpback Whale (Megaptera novaeangliae) mother and calf, Maui, Hawaii

Donald M. Jones / White-tailed Deer (Odocoileus virginianus) mother cleaning fawn, Montana

Donald M. Jones / White-tailed Deer (Odocoileus virginianus) doe cleaning newborn fawn, Montana

Donald M. Jones / White-tailed Deer (Odocoileus virginianus) doe smelling newborn fawn, Montana

Hiroya Minakuchi / African Elephant (Loxodonta africana) mothers and calves, Amboseli National Park, Kenya

Hiroya Minakuchi / African Elephant (Loxodonta africana) herd, Amboseli National Park, Kenya

Richard Du Toit / Northern Giraffe (Giraffa camelopardalis) mother and calf, Itala Game Reserve, KwaZulu-Natal, South Africa

Juergen & Christine Sohns / Swamp Wallaby (Wallabia bicolor) mother and joey, Mount Lofty, South Australia, Australia

Juergen & Christine Sohns / Eastern Grey Kangaroo (Macropus giganteus) mother with joey, Maloney Beach, New South Wales, Australia

Juergen & Christine Sohns / Eastern Grey Kangaroo (Macropus giganteus) mother with joey jumping, Maloney Beach, New South Wales, Australia

Suzi Eszterhas / Mallard (Anas platyrhynchos) rehabilitator, Isabel Luevano, with one day old orphan duckling, International Bird Rescue, Fairfield, California

Andrew Peacock / White Rhinoceros (Ceratotherium simum) mother and calf in grassland, Ol Pejeta Conservancy, Kenya

Sylvain Cordier / Polar bear (Ursus maritimus), female with two cubs, on a barrier island outside Kaktovik, Alaska, USA.

Juergen & Christine Sohns / African Elephant (Loxodonta africana) mother browsing with calves, Addo National Park, South Africa

Juergen & Christine Sohns / African Elephant (Loxodonta africana) mother and calf, Addo National Park, South Africa

Juergen & Christine Sohns / African Elephant (Loxodonta africana) mother and calf, Addo National Park, South Africa

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) mother and foal, Oshoto, Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) mother and foal, Oshoto, Wyoming

Anup Shah / Eastern Chimpanzee (Pan troglodytes schweinfurthii) sixteen month old baby female, named Gossamer, in tree, Gombe National Park, Tanzania

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) five year old juvenile female, named Fadhila, playing with her three year old brother, named Fifty, Gombe National Park, Tanzania

Chien Lee / Pygmy Anteater (Cyclopes didactylus) mother and young, Esmeraldas, Ecuador

Alfred Trunk/ BIA / Common Merganser (Mergus merganser) mother carrying chick, Upper Austria, Austria

Tui De Roy / Magellanic Penguin (Spheniscus magellanicus) parents and chicks along coast, Saunders Island, Falkland Islands

Tui De Roy / Magellanic Penguin (Spheniscus magellanicus) pair calling near chicks, Saunders Island, Falkland Islands

Paul Bertner / Fantastic Leaf-tail Gecko (Uroplatus phantasticus) mother and young, Ranomafana National Park, Madagascar

Paul Bertner / Giant Crab Spider (Sparassidae) mother with spiderlings, Udzungwa Mountains National Park, Tanzania

Michael Quinton / Dall's Sheep (Ovis dalli) ram, lamb, and ewe, Yukon Territory, Canada

Konrad Wothe / Common Merganser (Mergus merganser) mother with chicks, Upper Bavaria, Germany

Denis-Huot / Cheetah (Acinonyx jubatus) female with cubs sitting in long grass during the dry season, Masai-Mara Game Reserve, Kenya. March.

Ingo Arndt / Southern plains grey / Hanuman langur {Semnopithecus dussumieri} mother and baby, Jodhpur, Rajasthan, India

Ingo Arndt / Eastern grey kangaroo female with joey peering out of pouch {Macropus giganteus}. Wilson Promontory NP Australia

Richard Du Toit / Northern Giraffe (Giraffa camelopardalis) mother and calf, iSimangaliso Wetland Park, South Africa

Marion Vollborn/ BIA / Tiger (Panthera tigris) female with cubs, native to Asia

Marion Vollborn/ BIA / Tiger (Panthera tigris) female with cubs, native to Asia

Alain Ghignone/ BIA / Great Crested Grebe (Podiceps cristatus) pair feeding chick, Piedmont, Italy

SCOTLAND: The Big Picture / Golden eagle (Aquila chyrsaetos) female flying into nest site with small branch, Glen Tanar Estate, Cairngorms National Park, Scotland, UK, June.

Suzi Eszterhas / Common Wombat (Vombatus ursinus) foster mother, Linda Tabone, bottle feeding six month old orphaned joey, Bonorong Wildlife Sanctuary, Tasmania, Australia

Suzi Eszterhas / Common Wombat (Vombatus ursinus) orphan met by children, Bonorong Wildlife Sanctuary, Tasmania, Australia

Suzi Eszterhas / Pygmy Three-toed Sloth (Bradypus pygmaeus) mother and three month old young, Isla Escudo de Veraguas, Panama

Suzi Eszterhas / Pygmy Three-toed Sloth (Bradypus pygmaeus) mother and three month old young, Isla Escudo de Veraguas, Panama

Suzi Eszterhas / Pygmy Three-toed Sloth (Bradypus pygmaeus) mother and four month old young, Isla Escudo de Veraguas, Panama

Fiona Rogers / Eastern Chimpanzee (Pan troglodytes schweinfurthii) mother, twenty-three years old, holding less than one day old newborn, Gombe National Park, Tanzania

Franco Banfi / Mother with young calf Sperm whale (Physeter macrocephalus) Dominica, Caribbean Sea, Atlantic Ocean.

Tony Wu / Humpback whale (Megaptera novaeangliae) female breaching together with her male calf. The calf had a large wound on his left peduncle area, one that appeared to be the result of a large bite, Vava'u,...

Carol Walker / Wild pinto Mustang mare and foal running in Sand Wash Basin, Colorado, USA.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) females sitting close together with baby inbetween, Qinling Mountains, China.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) female with young suckling, Qinling Mountains, China.

Pete Oxford / White Rhinoceros (Ceratotherium simum) mother and calf with Red-billed Oxpeckers (Buphagus erythrorhynchus), South Africa

Anup Shah / Eastern chimpanzee (Pan troglodytes schweinfurtheii) female 'Gremlin' aged 41 years grooms her daughter 'Golden' aged 14 years while their infants 'Gizmo' aged 3 years and 'Glamma' aged 9 months sit b...

Suzi Eszterhas / Sea Otter (Enhydra lutris) mother with three day old newborn pup, Monterey Bay, California

Suzi Eszterhas / Sea Otter (Enhydra lutris) mother and three day old newborn pup, Monterey Bay, California

Suzi Eszterhas / Sea Otter (Enhydra lutris) mother and three day old newborn pup, Monterey Bay, California

Suzi Eszterhas / Sea Otter (Enhydra lutris) mother and six day old newborn pup, Monterey Bay, California

Tony Wu / Humpback whales (Megaptera novaeangliae) in a heat run, with six males competing for the attention of a female that already has a calf. Vava'u, Kingdom of Tonga

Tony Wu / Humpback whale (Megaptera novaeangliae), fluke of female with male calf playing below, Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale (Megaptera novaeangliae) calf nuzzling its mother, Vava'u, Kingdom of Tonga, Pacific Ocean.

Tony Wu / Humpback whale (Megaptera novaeangliae) and her calf pursued by males during heat run. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale calf (Megaptera novaeangliae) resting under the chin of its mother. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale (Megaptera novaeangliae) female with calf, pursued by males during heat run. Vava'u, Kingdom of Tonga. Pacific Ocean.

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

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

Denis-Huot / Masai giraffe (Giraffa camelopardalis tippelskirchi) baby standing below female, Maasai Mara Game Reserve, Kenya

Chien Lee / Ring-tailed Lemur (Lemur catta) mother carrying young, Berenty Private Reserve, Madagascar

Chien Lee / Ring-tailed Lemur (Lemur catta) mother carrying young, Berenty Private Reserve, Madagascar

Chien Lee / Verreaux's Sifaka (Propithecus verreauxi) mother and young, Berenty Private Reserve, Madagascar

Matthias Breiter / Black Bear (Ursus americanus) mother and cub in temperate rainforest, Anan Creek, Tongass National Forest, Alaska

Matthias Breiter / Polar Bear (Ursus maritimus) mother with cubs on coast, Barter Island, Alaska

Matthias Breiter / Black Bear (Ursus americanus) mother and cub in temperate rainforest, Anan Creek, Tongass National Forest, Alaska

Richard Du Toit / Burchell's Zebra (Equus burchellii) mother and foal, Rietvlei Nature Reserve, South Africa

Richard Du Toit / Burchell's Zebra (Equus burchellii) parents tending to foal, Rietvlei Nature Reserve, South Africa

Markus Varesvuo / Female Capercaillie (Tetrao urogallus) with newly hatched chick on nest, Kuhmo, Finland, June.

Markus Varesvuo / Female Capercaillie (Tetrao urogallus) with three chicks, Kuhmo, Finland, June.

Sergey Gorshkov / Leopard (Panthera pardus) mother licking cub, Londolozi, Sabi-sands Game Reserve, South Africa

Donald M. Jones / Elk (Cervus elaphus) bull and harem of females and calves along river, Athabasca River, western Canada

Donald M. Jones / Bighorn Sheep (Ovis canadensis) rams, ewe, and lamb, western Canada

Donald M. Jones / Bighorn Sheep (Ovis canadensis) ewes and lambs grazing, western Canada

Hiroya Minakuchi / African Elephant (Loxodonta africana) mother and calf, Amboseli National Park, Kenya

Hiroya Minakuchi / African Elephant (Loxodonta africana) herd walking, Amboseli National Park, Kenya

Fiona Rogers / Southern Plains Gray Langur (Semnopithecus dussumieri) newborn with mother, Jodhpur, Rajasthan, India

Anup Shah / African Lion (Panthera leo) female with cubs, Masai Mara, Kenya

Suzi Eszterhas / Harbor Seal (Phoca vitulina) mother and pup nuzzling, Monterey Bay, California