Western chimpanzee


The western chimpanzee, or West African chimpanzee, is a subspecies of the common chimpanzee. It inhabits western Africa, mainly in Côte d'Ivoire and Guinea but with populations in surrounding countries.

Etymology

The taxonomical genus Pan is derived from the Greek god of fields, groves, and wooded glens, Pan. The species name troglodytes is Greek for 'cave-dweller', and was coined by Johann Friedrich Blumenbach in his Handbuch der Naturgeschichte published in 1779. Verus is Latin for 'true', and was given to this subspecies in 1934 by Ernst Schwarz.
Originally Schwarz classified it as Pan satyrus verus.

Classification

The western chimpanzee is a subspecies of the common chimpanzee, along with the central chimpanzee, the Nigeria-Cameroon chimpanzee, and the eastern chimpanzee. They became genetically different from other chimpanzee subspecies approximately 500,000 years ago.

Conservation status

The IUCN lists the western chimpanzee as a critically endangered species on their Red List of Threatened Species. There are an estimated 21,300 to 55,600 individuals in the wild. The primary threat to the western chimpanzee is habitat loss, although it is also killed for bushmeat.

Distribution and habitat

The population of the western chimpanzee once spanned from southern Senegal all the way east to the Niger River. Today, the largest populations are found in Côte d'Ivoire and in Guinea. Other populations survive in Liberia, Sierra Leone, and Guinea-Bissau. Relict populations live in Ghana, Senegal, and Mali. The subspecies is extinct in the wild in the Gambia, and possibly Benin, Burkina Faso, and Togo.

Behavior

Diet and hunting

Male and female western chimpanzees differ in their prey. In Fongoli, Senegal, Senegal bushbabies account for 75% of females' prey and 47% of the males'. While males will prey more on monkeys, such as green monkeys and Guinea baboons, only males were observed to hunt patas monkeys and only females were observed to hunt banded mongooses. Both will occasionally hunt bushbucks, preferring fawns, when given the chance. Adult, adolescent, and juvenile females are slightly more likely to hunt with tools than males of the same age group.

Unique behaviors

Western chimpanzees have unique behaviors never observed in any of the other subspecies of the chimpanzee. They make wooden spears to hunt other primates, use caves as homes, share plant foods with each other, and travel and forage during the night. They also submerge themselves in water and play in it to stay cool in the oppressive heat. Unlike eastern chimpanzee communities where males jealously maintain borders to keep out nonresident males and even outright kill any outsider male who dares trespass into their community, there is evidence that male western chimpanzees can safely immigrate from their natal troop into neighbouring troops and even sire infants in several separate troops. There are even cases of solitary male western chimpanzees, while in any other chimpanzee population, a lone chimp could not survive for very long.

DNA

Western chimpanzees are the most genetically differentiated and homozygous subspecies of the common chimpanzee.