The Cross River gorilla is a critically endangered ape whose habitat is limited to a remote section of the border between Nigeria and Cameroon. This gorilla was named for the Cross River, a waterway that traverses both countries. This gorilla is one of two species of western gorilla, with the western lowland gorilla being the other. Sightings of the Cross River gorilla are so rare that it was believed to be extinct until late in the 20th century. Given the scientific name gorilla gorilla diehli in 1904, the scarcity of this species has made it difficult to study, so not as much is known about this type of gorilla as the other gorilla species.
Gorillas are the heaviest apes, and the Cross River gorilla weighs more than most, surpassed in size only by the eastern lowland gorilla. Although exact measurements aren’t available for these elusive creatures, it is believed that adult Cross River gorilla males average 396 pounds (180 kilograms). Fruit is their main dietary staple when in season, and they supplement it by eating leaves, bulbs, bark, ants, and flowers.
The low reproductive rate of the Cross River gorilla has made the survival of this species problematic. Females only reproduce once every four to six years, and generally only bear one baby at each birth. The females don’t start reproducing until they are about 10 years old, and each female generally doesn’t produce more than three or four offspring that survive to maturity during her lifetime. Cross River gorilla males don’t become sexually mature until even later, generally starting to breed at around the age of 15.
It is estimated that there are less than 300 Cross River gorillas left. The survivors are separated, having formed small, isolated groups, so inbreeding is another factor that has contributed to their declining numbers. They are also imperiled by humans, who hunt them for their meat and for their bones, which are used in healing remedies.
This hunting and the loss of habitat as their forest homes are being razed for logging and to create cropland have created a crisis for the survival of the species. Although it is difficult to compile precise statistics, it is believed that some years many more of these apes are killed than are born. Nigeria, Cameroon, and several wildlife agencies have targeted these gorillas for help, since the rapidly dwindling numbers make it apparent that this species will soon become extinct without human intervention.