The Cross River gorilla scientifically known as “Gorilla gorilla diehli” is a subspecies of the western gorilla (Gorilla gorilla) It is the most western and northern form of gorilla, and is restricted to the forested hills and mountains of the Cameroon-Nigeria border region at the headwaters of the Cross River in Nigeria.
It is separated by about 300 km from the nearest population of western lowland gorillas, and by around 250 km from the gorilla population in the Ebo Forest of Cameroon. Estimates from 2014 suggest that fewer than 250 mature Cross River gorillas remain, making them the world’s rarest great ape.
When comparing the Cross River gorilla to western gorillas, they have noticeably smaller palates, smaller cranial vaults, and shorter skulls. The Cross River gorilla is not known to differ much in terms of body size or limb and bone length from western gorillas.
However, measurements taken from a male suggest that they have shorter hands and feet and have a larger opposability index than western gorillas.