Claudio Contreras / Macaya breast-spot landfrog (Eleutherodactylus thorectes), critically endangered, Pic Macaya National Park, Massif de la Hotte, Haiti, October

Alan Williams / Male Ruddy Duck (Oxyura jamaicensis) displaying on lake expelling air from breast feathers to form bubbles (captive bird) UK, May 2010

Ross Hoddinott / Robin (Erithacus rubecula) resting on trowel handle in a garden, Nr Bradworthy, Devon, England, UK. January

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

David Tipling / X-ray of Hobby (Falco subbuteo) showing fractured wing and shot in breast from being hit by hunter, during BirdLife Malta Springwatch Camp, Malta, April 2013

Alex Mustard / 2020VISION / Robin (Erithacus rubecula) taking seeds from hand, New Forest National Park, Hampshire, UK, January, Model released. 2020VISION Book Plate. Did you know? Every Robin has a unique breast pattern - howe...

Fergus Gill / 2020VISION / Neck and breast plumage of Grey Heron (Ardea cinerea). Glasgow, Scotland, October.

Martin Willis / Blue-breasted Fairywren (Malurus pulcherrimus) male showing dark blue breast, Dryandra Woodland State Forest, Western Australia, Australia

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

David Tipling / 2020VISION / Eurasian nightjar (Caprimulgus europaeus) adult brooding chicks in nest, bill of chick visible under breast feathers, Suffolk Sandlings, Suffolk, UK, June

Graham Eaton / Mynydd Carnguwch, locally known as breast hill. Near Pwllheli, Wales, UK, May 2011.

Bryan and Cherry Alexander / Traditional Nenets toy cradle and baby made from a goose's breast bone. Yamal, Western Siberia, Russia, February 2007.

Colin Varndell / Close up of breast feathers of male Pheasant (Phasianus colchicus) UK, April

Claudio Contreras / Macaya breast-spot landfrog (Eleutherodactylus thorectes), critically endangered, Pic Macaya National Park, Massif de la Hotte, Haiti, October

Claudio Contreras / Macaya breast-spot landfrog (Eleutherodactylus thorectes), critically endangered, Pic Macaya National Park, Massif de la Hotte, Haiti, October

Claudio Contreras / Macaya breast-spot landfrog (Eleutherodactylus thorectes), critically endangered, Pic Macaya National Park, Massif de la Hotte, Haiti, October

Colin Varndell / Close-up of breast feathers of male Pheasant (Phasianus colshicus). Dorset, UK, April.

Colin Varndell / Breast plumage of male Common pheasant (Pheasianus colchicus) killed on the road, Dorset, UK April 2010

Edwin Giesbers / Orang utan (Pongo pygmaeus) head portrait of female, Semengoh Nature reserve, Sarawak, Borneo, Malaysia, Sarawak, Borneo, Malaysia, Endangered

Dave Watts / Common Buzzard (Buteo buteo) with white feather on breast, perched on tree branch in woodland, UK

Gerrit Vyn / Curve-billed Thrasher (Toxostoma curvirostre curvirostre) portrait, this subspeices has conspicuous breast spotting compared to Western birds. Hidalgo County, Texas, USA March.

Eric Baccega / Portrait of young Yali woman breast-feeding her baby. West Papua, former Irian-Jaya, Indonesia, August 2002 (West Papua).

Eric Baccega / Portrait of Dani woman breast-feeding her baby, Wamena, Baliem valley, West Papua, former Irian-Jaya, Indonesia, August 2002 (West Papua).

Roger Powell / Pair of Eclectus parrots (Eclectus roratus) near their breeding site. Female (on right) has missing neck and breast feathers after lining nest. Queensland, Australia

Alan Williams / Wood pigeon (Columba palumbus) on branch, calling shown by inflated breast, Essex, UK, June

Hanne & Jens Eriksen / Crowned sandgrouse {Pterocles coronatus} male collecting water for chicks in breast feathers, Jaaluni, Oman

Hanne & Jens Eriksen / Crowned sandgrouse {Pterocles coronatus} male collecting water for chicks in breast feathers, Jaaluni, Oman

Gerry Ellis / Olive Baboon (Papio anubis) female nursing infant, Gombe Stream National Park, Tanzania

Tom Vezo / Yellow-breasted Chat (Icteria virens), Rio Grande Valley, Texas

Tom Vezo / Rose-breasted Grosbeak (Pheucticus ludovicianus) male, Rio Grande Valley, Texas

Mark Raycroft / Wild Turkey (Meleagris gallopavo) male standing in snow showing breast tuft

Steven David Miller / Male Flock Bronzewing {Phaps histrionica} on ground with wings open, exposing underside of wing and breast, The Australia Zoo, Beerwah, Queensland, Australia

Jabruson / Egyptian rail (Pluvianus aegyptius) with wet breast feathers to help cool eggs in nest, Africa

Juergen Freund / Young Papuan woman with face tattoo breast feeding her baby, Tufi, Oro Province, Papua New Guinea

Tom Vezo / Great Crested Flycatcher (Myiarchus crinitus) with insect it has caught in its beak, perching, Adirondack Mountains, New York

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

Tom Vezo / Tropical Kingbird (Tyrannus melancholicus) perching on wire, Patagonia, Arizona

Tui De Roy / Red-footed Booby (Sula sula) white morph represents only five percent of the Galapagos population but is reverse elsewhere, Genovesa Tower Island, Galapagos Islands, Ecuador

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