Cyril Ruoso / Drill (Mandrillus leucophaeus) adult male appeasement face, Pandrillus Drill Sanctuary, Nigeria

Cyril Ruoso / Bonobo (Pan paniscus) smiling while laying on ground, ABC Sanctuary, Democratic Republic of the Congo

Paul D Stewart / Lithograph with contemporary colouring, continental version of the last wallchart produced by Benjamin Waterhouse Hawkins for the Department of Science and Art 1862. It is entitled 'Pachydermata and C...

Laurie Campbell / Golden eagle (Aquila chrysaetos) chick, one week, in eyrie showing egg-tooth on tip of bill, Argyll, Scotland, early May

Bryan and Cherry Alexander / Close up of Narwhal (Monodon monoceros) in water showing its ivory tooth, Northwest Greenland.

Sergey Gorshkov / Leopard (Panthera pardus) snarling, Botswana

Wild Wonders of Europe / Zankl / Newly hatched Loggerhead turtle (Caretta caretta) showing egg tooth used to break through shell, Dalyan Delta, Turkey, August 2009

Theo Allofs / Celebes Black Macaque (Macaca nigra) dominant male, Sulawesi, Indonesia

David Shale / Fang Tooth {Anoplogaster cornuta} close-up of head showing teeth, from the Mid-Atlantic Ridge, 2600m

Richard Du Toit / African Lion (Panthera leo) female growling, Masai Mara National Reserve, Kenya

Richard Du Toit / Burchell's Zebra (Equus burchellii) close-up of face of braying animal, Hluhluwe-umfolozi Game Reserve, South Africa

Mitsuaki Iwago / African Lion (Panthera leo) female roaring, Serengeti National Park, Tanzania