Facts about Cross River gorillas. "Scientific name for Cross River gorilla is Gorilla gorilla diehl". The Cross River gorilla has the species name G.g. diehli, full species name Gorilla gorilla diehl. The cross river gorilla is most closely related to the western lowland gorilla according to a 2001 genetic analysis. The Cross River gorilla and Western Lowland gorilla are though to have diverged as subspecies in the past few hundred thousand years, whereas the eastern and western gorillas diverged around two million years ago from a common ancestor.
There are two main species of gorillas, east and western lowland gorillas. They all live in equatorial Africa. These two populations are separated by the 600 miles (965 km) of the Congo Basin forest, an area filled with chimpanzees, bonobos and other primates. The eastern lowland gorillas and western lowland gorillas both have upland subspecies. The Cross River gorilla can be seen as the upland species of the western lowland gorilla. The Cross River gorilla lives in a small 300 square mile area that is geographically isolated from other gorilla populations.
Like all gorillas, Cross River Gorillas have arms much longer than their legs. And they walk on all fours, sometimes called knuckle walking. The males weigh three hundred to four hundred pounds (136 to 181 kg), while females weigh around two hundred pounds (90 kg). Females are four and a half to five feet tall (1.37 to 1.52 meters). Male Cross River gorillas are five and a half feet tall if upright (1.6 meters). Females reach sexual maturity at seven or eight years of age but rarely give birth until closer to age ten. The Cross River gorilla are pregnant for eight to nine months and give birth to babies somewhere between three and four pounds. The babies can grasp onto the mother’s fur from birth. They are nursed for up to three years before the female is receptive again. Female Cross River gorillas only have three or four offspring in a lifetime, meaning that the population takes centuries to rebound after a decline.
Females Cross River Gorillas tend to stay with their natal group, join neighboring groups or sometimes pair with single males. Males leave the group once they mature. They live alone until they establish their own territory or try to takeover their old family territory. Gorilla groups range from five to ten individuals, with one male and anywhere from two to five females. The group also includes babies and adolescents. Their home range varies in size from 2 to 11 1/2 square miles (five square kilometers to thirty square kilometers).
Cross River Gorillas diets shift with the elevation. The upland species of eastern and western gorillas live in montane forest at 4000 feet (1220 meters) and bamboo forests from 6000 feet (1830 meters) and higher elevations. The upland species of the eastern and western gorillas thus have teeth better adapted to the hard woody plants like bamboo than the softer plants available close to sea level.
Eastern gorillas are larger than western gorillas. The cross river gorilla has lighter hair on its silverback males than Western gorillas, and their silverback fur can stretch around to the thighs. On western gorillas, the silver hair grows on a well defined patch on the back.
The Cross River gorilla population of gorillas is critically endangered in the wild, with around 300 in the wild. Cross River gorillas only live in a small area in Cameroon and Nigeria. And unlike the Western lowland gorilla, there is no large captive population from which the wild population could be replenished.