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.
Elephant
At the beginning of the Pleistocene, elephantids experienced a high rate of speciation. The Pleistocene also saw the arrival of "Palaeoloxodon namadicus", the largest terrestrial mammal of all time. "Loxodonta atlantica" became the most common species in northern and southern Africa but was replaced by "Elephas iolensis" later in the Pleistocene. Only when "Elephas" disappeared from Africa did "Loxodonta" become dominant once again, this time in the form of the modern species. "Elephas" diversified into new species in Asia, such as "E. hysudricus" and "E. platycephus"; the latter the likely ancestor of the modern Asian elephant. "Mammuthus" evolved into several species, including the well-known woolly mammoth. Interbreeding appears to have been common among elephantid species, which in some cases led to species with three ancestral genetic components, such as the straight-tusked elephants. In the Late Pleistocene, most proboscidean species vanished during the Quaternary glaciation which killed off 50% of genera weighing over worldwide.