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
Genomic comparisons show that the Tapanuli orangutan separated from the Sumatran orangutan about 3.4 million years ago. The Tapanuli orangutan separated from the Bornean orangutan much later, about 670,000 years ago. The orangutans are the only surviving species of the subfamily Ponginae, which also included several other species, such as the three extinct species of the genus "Gigantopithecus", including the largest known primate, "Gigantopithecus blacki". The ancestors of the Ponginae split from the main ape line in Africa 16 to 19 million years ago (Mya) and spread into Asia.