Tim Fitzharris / Coast, Diamond Beach, Nusa Penida, Bali, Indonesia

Suzi Eszterhas / Chimpanzee (Pan troglodytes) feeding on Ugandan Red Colobus (Procolobus tephrosceles) monkey, western Uganda

Suzi Eszterhas / Chimpanzee (Pan troglodytes) pair feeding on Ugandan Red Colobus (Procolobus tephrosceles) monkey, western Uganda

Suzi Eszterhas / Chimpanzee (Pan troglodytes) feeding on Ugandan Red Colobus (Procolobus tephrosceles) monkey, western Uganda

Robin Chittenden / Portrait of a Western Red Colobus Monkey (Procolobus badius) Gambia, West Africa, January.

Robin Chittenden / Portrait of a Western Red Colobus Monkey (Procolobus badius). Gambia, West Africa, January.

Suzi Eszterhas / Western Red Colobus (Procolobus badius) pair in trees, Kibale Forest, Uganda

Konrad Wothe / Zanzibar Red Colobus (Procolobus kirkii) sitting in tree, endangered, Zanzibar

Konrad Wothe / Western Red Colobus (Procolobus badius) sitting in tree, Zanzibar

Thomas Mangelsen / Western Red Colobus (Procolobus badius) feeding on leaves in tree, Zanzibar, Tanzania

Mike Wilkes / Western red colobus monkey (Procolobus badius) sitting on ground, The Gambia, December