The greatest diversity of large mammals is found in the three National Parks. Akagera has typical savanna animals such as giraffes and elephants, while Volcanoes is home to about one third of the worldwide mountain gorilla population. Nyungwe Forest has thirteen primate species including chimpanzees and "Colobus" monkeys. The Ruwenzori colobus move in groups of up to 400, the largest troop size of any primate in Africa.