Cross River Gorilla

Lore & Background

The Cross River gorilla was first described as a new species of the western gorilla by Paul Matschie in 1904. Its morphological distinctiveness was confirmed in 1987. Subsequent analyses of cranial and tooth morphology, long bone proportions and distribution demonstrated its distinctiveness, and it was described as a distinct subspecies in 2000. In 2000, Esteban E. Sarmiento and John F. Oates proposed that the Cross River gorilla began to evolve into a distinct subspecies during an arid period of the African Pleistocene phase in response to declining food sources and a greater emphasis on herbivory and terrestrial behaviors.

In Their Own Story

Estimates on the number of Cross River gorillas remaining is 250–300 in the wild, concentrated in approximately 9-11 locations. Recent genetic research and field surveys suggest that there is occasional migration of individual gorillas between locations. The nearest population of western lowland gorilla is some 250 km (160 mi) away. Both loss of habitat and intense hunting for bushmeat have contributed to the decline of this subspecies. In 2007, a conservation plan for the Cross River gorilla was published, outlining the most important actions necessary to preserve this subspecies. The government of Cameroon has created the Takamanda National Park on the border with Nigeria, as an attempt to protect these gorillas. The park now forms part of an important trans-boundary protected area with Nigeria's Cross River National Park, safeguarding an estimated 115 gorillas—a third of the Cross River gorilla population—along with other rare species. The hope is that these gorillas will be able to move between the Takamanda reserve in Cameroon over the border to Nigeria's Cross River National Park.

Reader's Guide

The Cross River gorilla is critically endangered, with fewer than 250 mature individuals remaining as of 2014. Groups concentrate their activities in 11 localities across a 12,000 km² range, though recent field surveys suggest a wider distribution. Their habitats vary in altitude from approximately 100 to 2,037 metres above sea level. They prefer dense forest uninhabited by humans. Threats include deforestation, fragmentation, hunting, logging, agriculture, fuel wood harvesting, and exploitation of natural resources. Most regions they inhabit are legally protected, but some areas are not, such as between Kagwene Mountain and Upper Mbulu, and around Mone North.

Did You Know?

• The Cross River gorilla is separated by about 300 km from the nearest population of western lowland gorillas.
• In 2009, the Cross River gorilla was finally captured on professional video on a forested mountain in Cameroon.
• Cross River gorillas have been observed throwing sticks and clumps of grass when encountering humans, which is unusual as gorillas usually flee.
• Their nesting behavior varies by season: from April to November they are more likely to build nests in trees, and from November onward they are more likely to build nests on the ground.