Cyril Ruoso / Pygmy kingfisher (Ceyx picta) portrait, Cross River State, Nigeria. Non-ex

Cyril Ruoso / Chimpanzee (Pan troglodytes) baby playing with keeper, Pandrillus Drill Sanctuary, Nigeria

Cyril Ruoso / Chimpanzee (Pan troglodytes) adults and young, Pandrillus Drill Sanctuary, Nigeria

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

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

Cyril Ruoso / Drill (Mandrillus leucophaeus) adult female grooming alpha male, Pandrillus Drill Sanctuary, Nigeria

Cyril Ruoso / Drill (Mandrillus leucophaeus) adult male close-up of face, Pandrillus Drill Sanctuary, Nigeria

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

Anup Shah / Western lowland gorilla (Gorilla gorilla gorilla) juvenile female 'Bokata' aged 6 years walking bi-pedally to cross a river, Bai Hokou, Dzanga Sangha Special Dense Forest Reserve, Central African Repu...

Anup Shah / Western lowland gorilla (Gorilla gorilla gorilla) juvenile female 'Bokata' aged 6 years walking bi-pedally to cross a river, Bai Hokou, Dzanga Sangha Special Dense Forest Reserve, Central African Repu...

Anup Shah / Thomson's gazelles (Eudorcas thomsonii) following a herd of Wildebeest (Connochaetes taurinus) as they cross the Mara River, wide angle perspective, Masai Mara National Reserve, Kenya. September

Anup Shah / Eastern white-bearded wildebeest herd (Connochaetes taurinus) waiting to cross the Mara River. Masai Mara National Reserve, Kenya, October 2009