Franco Banfi / Sperm whale (Physeter macrocephalus) transparent chunk of skin in diver's hand, skin gets rubbed off when they socialise and groom each other by rubbing their massive bodies together, Dominica, Caribb...

Franco Banfi / Sperm whale (Physeter macrocephalus) transparent chunk of skin floating, skin gets rubbed off when they socialise and groom each other by rubbing their massive bodies together, Dominica, Caribbean Sea...

Richard Du Toit / Stone rubbed smooth by animals, mainly by White rhinoceros using it as a rubbing post, Rietvlei Nature Reserve, Gauteng Province, South Africa.

Jabruson / 'Ndembe' leaf close-up (Rothmannia welwitschi or macrocarpa) local people crush young leaves in hands and the juice squeezed on to baby and rubbed in for 'malade ti makako' (monkey disease). This affe...

Petra Wegner / Cavalier King Charles Spaniel, bitch, tricolour, having her belly rubbed. Model released

Piotr Naskrecki / Katydid (Phyllophora sp) leg with ridges used to produce hissing sound when rubbed against the sternum, Papua New Guinea

Petra Wegner / Cavalier King Charles Spaniel, ruby coated, being showered / bathed, in a bathtub, and rubbed dry with a towel. Sequence 16/16

Sharon Heald / Tree trunk on which elephants have rubbed the bark smooth, Chobe National Park, Botswana May 2008.

Peter Blackwell / Masai warrior, Eunoto ceremony, Mara, Kenya, hair rubbed with ochre,

Peter Blackwell / Masai warrior, sitting in hut doorway, Mara, Kenya, decorated with red ochre,

Peter Blackwell / Masai warrior, Eunoto ceremony, Mara, Kenya, hair rubbed with ochre,

Peter Blackwell / Masai warrior with shaved head, shiny with red ochre at Eunoto ceremony, Masai, Kenya

Donald M. Jones / White-tailed Deer (Odocoileus virginianus) rubbed trees by bucks, western Montana

Paul D Stewart / Illustration of 'Beagle laid ashore, River Santa Cruz'. Copperplate engraving, art by Conrad Martens, engraved by T. Landseer. Published by H. Colburn 1838. Plate from 'The Narrative of the Surveying...

Jim Brandenburg / Sioux Quartzite scratching post rubbed smooth by American Bison (Bison bison) over a period of hundreds of year, Touch the Sky Northern Tallgrass Prairie National Wildlife Refuge, Minnesota

Jim Brandenburg / Sioux Quartzite scratching post rubbed smooth by American Bison (Bison bison) over a period of hundreds of year, Touch the Sky Northern Tallgrass Prairie National Wildlife Refuge, Minnesota

Franco Banfi / A transparent sheet of shed skin from a Sperm whale (Physeter macrocephalus), resembling a plastic bag. The skin gets rubbed off when they socialize and groom each other by rubbing their massive bodie...