Fiona Rogers / Celebes / Black crested macaque (Macaca nigra) female with suckling infant aged 9-12 months, Tangkoko National Park, Sulawesi, Indonesia.

Fiona Rogers / Western chimpazee (Pan troglodytes verus) female 'Fanle' aged 13 years with suckling infant male 'Flanle' aged 3 years, Bossou Forest, Mont Nimba, Guinea. January 2011.

Steven Kazlowski / Moose (Alces alces) cow suckling her newborn calves. Tony Knowles Coastal Trail, Anchorage, south-central Alaska, May.

Florian Möllers / Quinling Golden snub nosed Monkey (Rhinopitecus roxellana qinlingensis), infant suckling Zhouzhi Nature Reserve, Qinling Mountains, Shaanxi, China.

Nick Turner / Gloucester old spot piglets (Sus scrofa domestica) suckling at the Cotswold Farm Show, Cirencester, UK, July 2008.

Nick Turner / Gloucester old spot piglets (Sus scrofa domestica) suckling at the Cotswold Farm Show, Cirencester, UK, July 2008.

David Woodfall / Grey Seal (Halichoerus grypus ) pup, 3 weeks, suckling. Donna Nook, UK, November.

Anup Shah / Caracal (Caracal caracal) two six month kittens suckling from mother, Masai Mara National Reserve, Kenya, August

Laurent Geslin / Two Southern plains grey / Hanuman langur {Semnopithecus dussumieri} females suckling young, Sariska NP, India

Anup Shah / Bonobo (Pan paniscus) baby aged 9-12 months, portrait, Lola Ya Bonobo Sanctuary, Democratic Republic of Congo. October.

Luiz Claudio Marigo / Capybara (Hydrochoeris hydrochaeris) mother with two suckling infants. The Pantanal wetlands of Mato Grosso State, Brazil, October.

Florian Möllers / Red fox (Vulpes vulpes) vixen nursing cubs in garden of block of flats, Berlin, Germany. May 2006

Anup Shah / Lion cub (Panthera leo) aged less than 2 days crying for its mother's attention while others suckle. Masai Mara National Reserve, Kenya, September 2009

Edwin Giesbers / Wild boar (Sus scrofa) female with piglets from two different litters, the Netherlands, April

Petra Wegner / British Longhair Cat (Highlander, Lowlander, Britanica) blue-cream-white coated, lying and nursing ginger kittens, aged 2 weeks.

Petra Wegner / British Longhair Cat (Highlander, Lowlander, Britanica) blue-cream-white coated, cloe up lying and nursing ginger kittens, aged 2 weeks.

Petra Wegner / British Longhair Cat (Highlander, Lowlander, Britanica) blue-cream-white coated, lying and nursing ginger kittens, aged 2 weeks.

Petra Wegner / British Longhair Cat, blue-cream-silver-tabby-mackerel (Highlander, Lowlander, Britanica) lying down with kittens, aged 3 weeks.

Petra Wegner / British Longhair Cat, blue-cream-silver-tabby-mackerel (Highlander, Lowlander, Britanica) lying down with kittens, aged 3 weeks.

Petra Wegner / British Longhair Cat, blue-cream-silver-tabby-mackerel (Highlander, Lowlander, Britanica) lying down and grooming ginger kitten, aged 3 weeks.

Petra Wegner / British Longhair Cat, blue-cream-silver-tabby-mackerel (Highlander, Lowlander, Britanica) lying down and grooming ginger kitten, aged 3 weeks.

Anup Shah / Impala herd (Aepyceros melampus) and female with suckling fawn in late afternoon rain, Masai Mara National Reserve, Kenya. March.

Anup Shah / African elephant (Loxodonta africana) calf aged 3-6 months wanting to suckle, Masai Mara National Reserve, Kenya. March.

Wild Wonders of Europe / Shpilenok / Saiga antelope (Saiga tatarica) with two calves suckling near Cherniye Zemli (Black Earth) Nature Reserve, Kalmykia, Russia, May 2009

Guy Edwardes / Young Grey Seal {Halichoerus grypus} taking a break from suckling from mother, Donna Nook, Lincolnshire, England, January

Dan Burton / Piglets suckling {Sus scrofa domestica} UK

Anup Shah / Leopard {Panthera pardus} with young suckling, Serengeti NP, Tanzania

Yva Momatiuk & John Eastcott / Masai Giraffe (Giraffa tippelskirchi) mother nursing newborn, Masai Mara, Kenya

Jean-Pierre Zwaenepoel / Southern plains grey / Hanuman langur {Semnopithecus dussumieri} mother and young sitting on roof, Jodhpur, India

Jane Burton / Domestic Cat {Felis catus} Tabby mother suckling her kittens.

Hermann Brehm / Argentine grey / Patagonian fox suckling young {Pseudolopex griseus} Torres del Paine NP, Chile

Jane Burton / Domestic cat (Felis catus) suckling 2/3-week-old kittens

Colin Seddon / Suckler cow suckling calf {Bos taurus} on organic Farm, Berkshire, England UK

Mike Wilkes / Exmoor pony mare {Equus caballus} and foal suckling. Exmoor National Park, UK.

Mary McDonald / Harp seal pup {Phoca groenlandicus} suckling. Canada.

LYNN M. STONE / Domestic Texas longhorn cow suckling calf {Bos taurus}, Texas Hill Country, USA

Mats Forsberg / Ringed seal pup suckling {Phoca hispida} Svalbard, Norway

Pete Cairns / Eriskay pony with foal suckling {Equus caballus} South Uist, Scotland, UK

David Welling / Common seal mother feeding 2 day pup {Phoca vitulina} La Jolla Cove, California, USA

Anup Shah / Orang utan mother with baby suckling, (Pongo abelii) Gunung Leuser NP, Indonesia

Anup Shah / Cheetah mother suckling cubs in lair in long grass {Acinonyx jubatus} Masai Mara

Anup Shah / Leopard suckling cub {Panthera pardus}, Masai Mara Game Reserve, Kenya

Gerry Ellis / African Elephant (Loxodonta africana) infant begging mother to nurse, Amboseli National Park, Kenya

Matthias Breiter / Grizzly Bear (Ursus arctos horribilis) adult female nursing her two yearling cubs on sedge flats, Katmai National Park, Alaska

Sumio Harada / Red Squirrel (Tamiasciurus hudsonicus) mother nursing her 19 day old babies in nest in tree trunk, Rocky Mountains, North America

Sumio Harada / Red Squirrel (Tamiasciurus hudsonicus) mother nursing her 15 day old babies in nest, Rocky Mountains, North America

Sumio Harada / Red Squirrel (Tamiasciurus hudsonicus) mother nursing babies in nest, Rocky Mountains, North America

Jim Brandenburg / American Bison (Bison bison) mother with nursing calf, South Dakota

Tui De Roy / Galapagos Sea Lion (Zalophus wollebaeki) newborn pup nursing, Cape Douglas, Fernandina Island, Galapagos Islands, Ecuador

Anup Shah / Cheetah mother suckling very young cubs {Acinonyx jubatus} Masai Mara, Kenya

Anup Shah / Leopard suckling cubs {Panthera pardus} Masai Mara, Kenya

Anup Shah / African elephant mother with suckling calf {Loxodonta africana} Masai Mara, Kenya

TJ Rich / Roe deer mother suckling fawn {Capreolus capreolus} UK

TJ Rich / Roe deer mother suckling fawn {Capreolus capreolus} UK

Karl Ammann / Olive baboon mother with young {Papio anubis} Samburu Reserve, Kenya

Andrew Cooper / Red Fox vixen suckling cubs in den, Devon, England.

Anup Shah / Newborn Common zebra foal suckling {Equus quagga} Masai Mara NR, Kenya

Jabruson / Mountain gorilla family, mother suckling young + male silverback in background {Gorilla g beringei} Virunga NP, Dem Rep Congo

Asgeir Helgestad / European Brown bear suckling cubs {Ursus arctos} Finland

Nick Gordon / Jaguar female and 4-day-old cub in birth den {Panthera onca} Amazonia, Brazil, South America. Captive.

Anup Shah / Lion female suckling litter Masai Mara, Kenya

Anup Shah / Giraffe suckling with male testing urine of female Giraffa camelopardalis} Kenya

Alex Hyde / Gloucestershire Old Spot piglets (Sus scrofa domestica) suckling from sow. Stonebridge City Farm in central Nottingham, UK, October.

Ann & Steve Toon / White rhinoceros (Ceratotherium simum) calf suckling from mother, Lake Nakuru National Park, Kenya

Fiona Rogers / Celebes / Black crested macaque (Macaca nigra) female with her suckling baby aged less than 1 month, Tangkoko National Park, Sulawesi, Indonesia.

Anup Shah / Celebes / Black crested macaque (Macaca nigra) female with suckling baby aged less than 1 month, Tangkoko National Park, Sulawesi, Indonesia.

Anup Shah / Celebes / Black crested macaque (Macaca nigra) female sitting in a tree with her playful baby aged less than 1 month, Tangkoko National Park, Sulawesi, Indonesia.

Anup Shah / Celebes / Black crested macaque (Macaca nigra) female grooming suckling infant, Tangkoko National Park, Sulawesi, Indonesia.

Anup Shah / Celebes / Black crested macaque (Macaca nigra) female with suckling infant aged 9-12 months, Tangkoko National Park, Sulawesi, Indonesia.

Denis-Huot / Masai Giraffe (Giraffa camelopardalis tippelskirchi), young suckling from its mother. Masai-Mara game reserve, Kenya.

Denis-Huot / Masai Giraffe (Giraffa cameleopardalis tippelskirchi), young suckling from its mother. Masai-Mara game reserve, Kenya.

Denis-Huot / African Elephant (Loxodonta africana), baby suckling its mother. Masai-Mara Game Reserve, Kenya.

Denis-Huot / African Elephant (Loxodonta africana), young suckling from its mother. Amboseli National Park, Kenya.

Denis-Huot / African Elephant (Loxodonta africana) young suckling from its mother. Amboseli National Park, Kenya.

Denis-Huot / African Elephant (Loxodonta africana) baby suckling its mother. Masai-Mara Game Reserve, Kenya.

Sue Flood / Northern fur seals (Callorhinus ursinus) breeding colony with male, female and new born pups all resting on Tyuleniy Island, Russian Far East, June.

Sue Flood / Northern fur seal (Callorhinus ursinus) female nursing new born pup with others behind, Tyuleniy Island, Russian Far East, June

David Pattyn / Capybara (Hydrochoerus hydrochaeris) family group with female suckling the young, Pantanal, Brazil.

Anup Shah / Western chimpanzee (Pan troglodytes verus) female 'Fanle' aged 13 years with suckling male infant 'Flanle' aged 3 years being groomed by alpha male 'Foaf' aged 30 years, Bossou Forest, Mont Nimba, G...

Anup Shah / Western chimpanzee (Pan troglodytes verus) females 'Jire' aged 52 years and 'Fanle' aged 13 years with suckling infant male 'Flanle' aged 3 years using rocks as tools to crack open palm oil nuts, Bo...

Anup Shah / Western chimpanzee (Pan troglodytes verus) females 'Jire' aged 52 years and 'Fanle' aged 13 years with suckling infant male 'Flanle' aged 3 years using rocks as tools to crack open palm oil nuts, Bo...

Anup Shah / Western chimpanzee (Pan troglodytes verus) females 'Jire' aged 52 years and 'Fanle' aged 13 years with suckling infant male 'Flanle' aged 3 years using rocks as tools to crack open palm oil nuts, Bo...

Anup Shah / Western chimpanzee (Pan troglodytes verus) female 'Fanle' aged 13 years with her suckling son 'Flanle' aged 3 years sitting with female 'Jire' aged 52 years, Bossou Forest, Mont Nimba, Guinea. Janua...

Anup Shah / Western chimpanzee (Pan troglodytes verus) infant male 'Flanle' aged 3 years trying to suckle from his mother 'Fanle' aged 13 years while she tries to crack nuts, Bossou Forest, Mont Nimba, Guinea....

Anup Shah / Western chimpanzee (Pan troglodytes verus) female 'Fanle' aged 13 years grinning due to stress as her infant son 'Flanle' aged 3 years struggles to suckle, Bossou Forest, Mont Nimba, Guinea. January...

Fiona Rogers / Western chimpazee (Pan troglodytes verus) female 'Fanle' aged 13 years with suckling male infant 'Flanle' aged 3 years being groomed by alpha male 'Foaf' aged 30 years, Bossou Forest, Mont Nimba, Guin...

Fiona Rogers / Western chimpazee (Pan troglodytes verus) female 'Fanle' aged 13 years with suckling male infant 'Flanle' aged 3 years being groomed by alpha male 'Foaf' aged 30 years, Bossou Forest, Mont Nimba, Guin...

Fiona Rogers / Western chimpazee (Pan troglodytes verus) infant male 'Flanle' aged 3 years trying to suckle from his mother 'Fanle' aged 13 years while she tries to crack nuts, Bossou Forest, Mont Nimba, Guinea. Jan...

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) mother nursing cub, Lake Clark National Park, Alaska

Jabruson / African Forest elephant (Loxodonta africana cyclotis) calf suckling from mother, whilst visiting Dzanga Bai, Dzanga-Ndoki National Park, Central African Republic

Jabruson / African domestic goat female with suckling kid, sheltering under the eves of a village house in wet season, Boukoko village, Central African Republic

Winfried Wisniewski / Beisa Gemsbok (Oryx gazella beisa) mother nursing calf, Samburu-Isiolo Game Reserve, Kenya

Colin Monteath / Fjord Horse (Equus caballus) mare nursing foal, Timaru, New Zealand

Mark MacEwen / Marsh pride lioness suckling cubs (Panthera leo) at night Masai Mara, Kenya. Taken with infra-red camera, September

Mark MacEwen / Marsh pride lioness suckling cubs (Panthera leo) at night, Masai Mara, Kenya. Taken with infra-red camera, September

Ernie Janes / Gloucester Oldspot Piglets (Sus scrofa domestica) in sty. UK