Thomas Marent / Mandrill (Mandrillus sphinx) male in defensive posture, Lekedi Natural Preserve, Gabon

Cyril Ruoso / Drill (Mandrillus leucophaeus) alpha male calling, Pandrillus Drill Sanctuary, Cross River State, Nigeria

Daniel Heuclin / Green tree snake (Phyllodryas viridissima) on a branch about to stike, Bolivian Amazonia, controlled conditions

Juergen Freund / Researchers Guido and Katja Westhoff work in a mobile lab in the bush. To handle the deadly Common death adder (Acanthophis antarcticus) Guido puts the head and upper portion of the snake in a plastic...

Charlie Summers / African lion (Panthero leo) male giving flehmen grimace, Tanzania, East Africa

Stephen Dalton / Green cat snake (Boiga cyanea) striking, a rear-fanged arboreal rainforest species, controlled conditions, from India and SE Asia

Stephen Dalton / Green cat snake (Boiga cyanea) defensive behaviour, a rear-fanged arboreal rainforest species, controlled conditions, from India and SE Asia

Mark Bowler,Mark Bowler / Siberian musk deer (Moschus moschiferus) male with tusks grooming, captive, Midlothian deer enclosure, UK, vulnerable species

Michael & Patricia Fogden / Vampire Bat (Desmodus rotundus) portrait, Costa Rica

Pete Oxford / Close up of Emerald tree boa's mouth and fangs {Corallus canina} Guyana - snake

LYNN M. STONE / Fangs of Eastern diamondback rattlesnake. Florida, USA {Crotalus adamanteus}

Pete Oxford / Two striped forest pit viper snake with young, fangs open {Bothriopis bilineatus} Amazon rainforest, Ecuador