Anup Shah / Bornean Orangutan (Pongo pygmaeus wurmbii) female baby 'Petra' aged 12 months. Camp Leakey, Tanjung Puting National Park, Central Kalimantan, Borneo, Indonesia. July 2010. Rehabilitated and released (...

Suzi Eszterhas / Sumatran Orangutan (Pongo abelii) two and a half year old baby calling, Gunung Leuser National Park, north Sumatra, Indonesia

Mark Bowler / Sustainable river fishing for Silver Arowana / Arahuana (Osteoglossum bicirrhosum) for the tropical fish trade - baby Arowana fish fry are harvested from the adult male (this species is a mouth broode...

Mark Bowler / Red howler monkey (Alouatta seniculus) howling, captive, digitally modified

ZSSD / Chimpanzee (Pan troglodytes) calling while reclining, native to Africa

TJ Rich / Portrait of male silverback Western Lowland gorilla {Gorilla gorilla gorilla} with fingers in mouth UK

Thomas Marent / Barbary Macaque (Macaca sylvanus) mother with young sticking finger into its mouth, native to northern Africa

Thomas Marent / Barbary Macaque (Macaca sylvanus) mother with young sticking finger into its mouth, native to northern Africa

Mark Carwardine / Spectacled caiman {Caiman crocodilus} young held in hand, mouth wide open, Rio Negro, near Manaus, Brazil, Amazonia

Mark Carwardine / Keiko, Killer whale star of Free Willy, fed by handler, Oregon, USA {Orcinus orca}

Tom Vezo / Broad-billed Hummingbird (Cynanthus latirostris) male being measured, Arizona

Petra Wegner / Hand feeding strawberry to Female Greek tortoise (Testudo hermanni boettgeri) waiting with mouth open, model released

Daniel Heuclin / Bonobo (Pan paniscus) head portrait with hand in mouth, Congo, Central Africa, captive

Pete Oxford / Medium Ground Finch (Geospiza fortis) getting bill length measured, part of avian pox research, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Woolly Opossum (Caluromys philander) young in defensive display, Rupununi, Guyana

Daniel Heuclin / Asp viper (Vipera aspis) with head held in hand, and mouth open to show venomous fangs. France, Europe. Controlled conditions.

Suzi Eszterhas / Sumatran Orangutan (Pongo abelii) two and a half year old baby, Gunung Leuser National Park, north Sumatra, Indonesia

Jane Burton / Golden Retriever dog mouth fencing with owner's hand

Mark Moffett / Army Ant (Eciton hamatum) major worker biting human. Also called a soldier, its primary job is defending the colony, Barro Colorado Island

Mark Moffett / Army Ant (Eciton hamatum) major worker or soldier, whose main job is defending the colony, biting human finger with sharp and powerful mandibles, Barro Colorado Island, Panama

Tom Vezo / Bald Eagle (Haliaeetus leucocephalus) chick having measurements taken, Camp Verde, Arizona

Michael Durham / Oregon Division of Fish and Wildlife biologist Pat Matthews collects data on a newborn Elk (Cervus elaphus) calf in the Sled Springs Elk Study Area, the calf will be radio collared so that its movemen...

LYNN M. STONE / Eastern diamondback rattlesnake held in hand with mouth showing fangs and venom (Crotalus admanteus) Florida, USA Captive

Heidi & Hans-Juergen Koch / African Clawed Frog (Xenopus laevis) swimming underwater showing underside and front feet, aquatic, rarely seen out of water, native to Africa

Pete Oxford / Brown Capuchin (Cebus apella) licking fingers after drinking from Piassava Palm (Attalea funifera) nut, Cerrado habitat, Piaui State, Brazil

Flip Nicklin / Squid beaks retrieved from Sperm Whale (Physeter macrocephalus) feces, Sri Lanka

Flip Nicklin / Squid beaks found in Sperm Whale (Physeter macrocephalus) feces, Sri Lanka

Mark Moffett / Chinese Habu (Trimeresurus mucrosquamatus) being milked for venom, Tam Dao National Park, Vietnam

Steven David Miller / Hand stencils, Aborigine rock art, Nanguluwur site, Kakadu NP, Australia - paint sprayed from mouth around hand

Thomas Marent / Barbary Macaque (Macaca sylvanus) mother with young sticking finger into its mouth, native to northern Africa

Pete Oxford / Brown Capuchin (Cebus apella) licking fingers after drinking from Piassava Palm (Attalea funifera) nut, Cerrado habitat, Piaui State, Brazil

Pete Oxford / Domestic Cattle (Bos taurus) being caught and branded by Chagra cowboys at a hacienda during the annual overnight cattle round-up, Andes Mountains, Ecuador

Pete Oxford / Domestic Cattle (Bos taurus) being caught and branded by Chagra cowboys at a hacienda during the annual overnight cattle round-up, Andes Mountains, Ecuador