Wildlife of Sierra Leone
Sierra Leone has 15 identified species of primates that include bushbaby, monkeys and a great ape, the common chimpanzee which is Sierra Leone's largest primate. Chimpanzees are found across the country with the 2010 chimpanzee census estimated a wild population in excess of 5500 more than double the number previously thought to live in the country. This is the second largest population of the endangered subspecies of western chimpanzee, after Guinea,
with the largest density in the Loma area, 2.69 individuals per km2, and the Outamba, with 1.21 individuals per km2.
Orangutan
The three orangutan species are the only extant members of the subfamily Ponginae. This subfamily also included the extinct genera "Lufengpithecus", which lived in southern China and Thailand 2–8 mya, and "Sivapithecus", which lived India and Pakistan from 12.5 mya until 8.5 mya. These apes likely lived in drier and cooler environments than orangutans do today. "Khoratpithecus piriyai", which lived in Thailand 5–7 mya, is believed to have been the closest known relative of the orangutans. The largest known primate, "Gigantopithecus", was also a member of Ponginae and lived in China, India and Vietnam from 5 mya to 100,000 years ago.