Klein & Hubert / Cotentin domestic donkey (Equus africanus asinus) jenny nuzzling newborn foal, France.

Tui De Roy / Erect-crested penguin (Eudyptes sclateri) pair in greeting display. Antipodes Island, New Zealand Sub-Antarctic Islands. Endemic to Antipodes and Bounty Islands. Endangered species.

Jane Burton / Blue and white Burmese-cross kitten rubbing against sooty-fawn dwarf Rex rabbit. NOT AVAILABLE FOR BOOK USE

Nick Upton / Grey seal (Halichoerus grypus) pup resting on a sandy beach, stretching and rubbing its head with its flipper, Norfolk, England, UK, January.

Fred Olivier / Northern sea otter (Enhydra lutris kenyoni) grooming, rubbing face, Kachemak Bay, Alaska, USA.

Fred Olivier / Close-up of a Northern sea otter (Enhydra lutris kenyoni) rubbing face, Kachemak Bay, Alaska, USA.

Fred Olivier / Northern sea otter (Enhydra lutris kenyoni) grooming, Kachemak Bay, Alaska, USA.

Fred Olivier / Close-up of a Northern sea otter (Enhydra lutris kenyoni) rubbing face, Kachemak Bay, Alaska, USA.

Fred Olivier / Close-up of a Northern sea otter (Enhydra lutris kenyoni) grooming, Kachemak Bay, Alaska, USA.

Fred Olivier / Close-up of a Northern sea otter (Enhydra lutris kenyoni) sleeping, wakes up and rubs head, grooming, Kachemak Bay, Alaska, USA.

Bruno D'Amicis / Marsican / Apennine brown bear (Ursus arctos marsicanus) checking rub-tree for scent. Critically endangered subspecies. Abruzzo, Lazio and Molise National Park / Parco Nazionale d'Abruzzo, Lazio e...

Eric Baccega / African elephant (Loxodonta africana) rubbing bottom against boundary stone, Akagera National Park, Rwanda, Africa, Vulnerable species.

Eric Baccega / African elephant (Loxodonta africana) rubbing against boundary stone, Akagera National Park, Rwanda, Africa, Vulnerable species.

Remi Masson / Group of Wels catfish (Silurus glanis) rubbing against each other, with very large individual over two metres long, River Rhone, Rhone-Alpes, France, September.

Stephane Granzotto / Red deer (Cervus elaphus) stag rubbing antlers on tree during rut, Rhone-Alpes, France, October.

Eric Medard / Male Roe deer (Capreolus capreolus) in velvet rubbing against a tree, France, January.

Edwin Giesbers / Red deer (Cervus elaphus) stag rubbing antlers on the ground during rut, Richmond Park, London, England, UK. October.

Dave Bevan / Male Pere David's deer (Elaphurus davidianus) rubbing antlers on ground, marking territory, Carmarthenshire, Wales, UK. September. Captive.

Carol Walker / Head portrait of black Andalusian stallion and mare meeting for the first time in southern Spain, Europe.

Carol Walker / RF - Head portrait of black Andalusian mare and stallion meeting for the first time in Spain, Europe. (This image may be licensed either as rights managed or royalty free.)

David Tipling / RF - Antarctic fur seal (Arctocephalus gazella) pup on Albatross Island, South Georgia. January. (This image may be licensed either as rights managed or royalty free.)

Richard Du Toit / Zebra (Equus quagga) rubbing head on front leg, Rietvlei Nature Reserve, Gauteng Province, South Africa, December.

Klein & Hubert / Domestic domestic donkey and foal (Equus africanus asinus) in meadow, Austria.

Klein & Hubert / Cotentin domestic donkey (Equus africanus asinus) two foals aged one month, playing, France.

Klein & Hubert / Outdoor free range young domestic mixed breed Pietrain and Landrace pigs (Sus scrofa domesticus) rubbing against straw bales used as shelter, Germany,

Klein & Hubert / Outdoor free range domestic Pig (Sus scrofa domesticus) rubbing against straw bale shelter, Germany.

Klein & Hubert / Outdoor free range domestic Pig (Sus scrofa domesticus) scratching after mud bath, Germany.

Eric Baccega / Reindeer (Rangifer tarandus) herd in spring. Yar-Sale district, Yamal, Northwest Siberia, Russia. April.

Danny Green / Atlantic Puffins (Fratercula arctica) pair bill rubbing, part of ritual courtship, Skomer Island, Wales, UK, May

George Sanker / Elk (Cervus elaphus) bull rubbing against pine tree, Jasper National Park, Alberta, Canada.

Brent Stephenson / Two young Southern elephant seal (Mirounga leonina) males play fighting, with King penguins (Aptenodytes patagonicus) in the background, Gold Harbour, South Georgia, South Atlantic, January.

Brandon Cole / Grey Whale (Eschrichtius robustus) curious adult whale allowing tourist to rub its head, Magdalena Bay, Baja, Mexico.

Nick Upton / Dan Jarvis giving 'Ray', a brain damaged adult male Grey seal (Halichoerus grypus) a rub with a broom at the Cornish Seal Sanctuary where he is a long term resident alongside recovering pups, Gweek, C...

Nick Upton / Dan Jarvis giving 'Ray' a brain damaged adult male Grey seal (Halichoerus grypus) a rub with a broom at the Cornish Seal Sanctuary. Gweek, Cornwall, UK, November. Model released.

Denis-Huot / Lioness (Panthera leo) playing with a lost baby Wildebeest (Connochaetes taurinus), Masai-Mara Game Reserve, Kenya

Erlend Haarberg / Muskox (Ovibos moschatus) covered by snow, Dovrefjell-Sunndalsfjella National Park, Norway, February.

Roy Mangersnes / Polar bear (Ursus maritimus) rubbing eye and stretching in spring snow, Svalbard, Norway, June.

Andy Rouse / Bengal tiger (Panthera tigris tigris) female 'T19 Krishna' with 11 month cub, Ranthambore National Park, India.

Andy Rouse / Bengal tiger (Panthera tigris tigris) female 'T19 Krishna' with 11 month cub, Ranthambore National Park, India.

Staffan Widstrand / American Bison (Bison bison) rubbing against tree, Yellowstone National Park, Wyoming, USA

John Abbott / Mountain Buffalo (Bison bison athabascae) rubbing against tree at wallow, British Columbia, Canada. July.

John Abbott / Mountain Buffalo (Bison bison athabascae) rubbing against tree at wallow, British Columbia, Canada. July.

Alex Mustard / RF- Pair of Rock beauties (Holacanthus tricolor) spawning at dusk. The larger male rubs against the flank of female during the spawning rise. Cayman Islands, British West Indies. Caribbean Sea. (This...

Todd Mintz / Bowhead Whale (Balaena mysticetus) rubbing off flaking skin on the ocean bottom, east coast Baffin island, Qikiqtarjuaq, Nunavut, Canada, May.

Alex Mustard / Group of smaller male Tarpon (Megalops atlanticus) rub along the flanks of a larger female during courtship as they swim over Coral reef. George Town, Grand Cayman, Cayman Islands, British West Indies...

Jeff Rotman / A Capuchin monkey (Cebus sp) uses a cloth to rub its owner's face and relieve her of itching. The monkey is trained to be a companion and assistant for its owner, who has physical disabilities, and it...

John Waters / Common starling {Sturnus vulgaris} anting, pecking at ant's nest to rub ants into plumage to clear parasites from feathers, juvenile, captive bird, Somerset, UK

John Waters / Common starling {Sturnus vulgaris} anting, pecking at ant's nest to rub ants into plumage to clear parasites from feathers, juvenile, captive bird, Somerset, UK