Cross River gorilla is a subspecies of western gorilla also known as Gorilla Gorilla Diehli, this species was identified as a spate species by Paul Matchie in 1904 but its populations were not systemically surveyed until 1987. Cross River gorillas are the most endangered species of gorillas with a survey of 2014 estimating only 250 mature adults in the wild, the population is said to have declined by 59% between 1995 and 2010.
The cross river gorillas have been identified to be having smaller pallets, smaller dentitions, shorter skulls and smaller cranial vaults, cross river gorillas were identified to be having a barrel chest making them the largest living primates in the world.
Cross River gorillas also have shorter hands and feet with large opposability index than western gorillas. The adult males have an average height of 165-175cm tall and females 140cm adult males weigh between 140-200 kilograms and females can weigh up to 100 kilograms.
Cross River gorillas inhabit highlands around Nigeria-Cameroon border, the cross river gorillas have different ways of building nests for example from April to November they prefer to build their nests on top of trees and build it on nests after November. Day nest construction is common in the dry seasons than in wet seasons.
Cross gorilla groups mainly comprise of 1 dominating silverback and 6 females with their offsprings compared to other gorilla species, they feed on terrestrial herbs, fruits, bark, vegetation, leaves and so much more.
Cross mountain gorillas have been discovered to use tools such as throwing grass and branches at researchers. There is little information known about their reproduction though scientists agree that the gestation period is about 8.5 months.
About Western Gorillas
Western lowland gorillas and cross lowland gorillas are all subspecies of the western gorillas, this subspecies of gorilla had a population of about 100,000 in the 1980s but the population had dramatically decreased by 2007 due to poaching, diseases and habitat loss.
Western low land gorillas have a low birth rate just like other gorilla species having only 1-2 fertile days in a month. Female gorillas start producing at the age of 10-12 years and can produce only 4-6 offsprings in a lifetime, baby gorillas are vulnerable just like human babies at birth and feed on breast milk up to the age of about 3-4 years old.
Western low land gorillas are mainly herbivores like all other gorilla species feeding on pulp, celery, tree bark, leaves, shoot, fruits and stems though they sometimes supplement their diet with ants, termites and insects. Adult gorillas can eat up to 18 kilograms of vegetation in a day.
Western gorillas home range can reach 8-45 kilometres range and can move for 3-5 kilometres per day, the gorilla families are dominated by dominant silverbacks that conduct all the group activities and access all the females in the group.
