The Cross River Gorilla is a subspecies of the western gorilla found exclusively along the border of Nigeria and Cameroon. The International Union for Conservation of Nature (IUCN) recognizes this primate as critically endangered, the highest threat classification for a species in the wild. This makes it the most threatened great ape on the African continent. Its decline is driven by human activities that have reduced its habitat and directly targeted its populations.
Population Size and Geographic Isolation
The total population of the Cross River Gorilla is estimated to be fewer than 300 individuals remaining in the wild, making every loss a significant blow to the subspecies’ future. These gorillas are scattered across a trans-boundary range in at least 11 different localities across a rugged landscape.
Their distribution is confined to the forested hills and mountains at the headwaters of the Cross River, separating them from the nearest populations of Western Lowland Gorillas. The groups are geographically isolated, sometimes by over 50 kilometers, which prevents regular movement and genetic exchange. This separation creates small, distinct meta-populations susceptible to localized extinction events from disease or human conflict.
Habitat Loss and Fragmentation
The primary long-term threat to the subspecies is the loss and fragmentation of its limited forest home. The gorilla’s habitat, a mix of montane and lowland forests, is under pressure from an increasing human population in the surrounding areas. This encroachment has pushed the gorillas into higher-altitude, less-accessible terrain, reducing the availability of diverse food sources.
A main driver of habitat destruction is the conversion of forest land for subsistence agriculture, often involving “slash-and-burn” techniques. As local populations expand, forest is cleared to grow crops, removing the land gorillas rely on for foraging and nesting. This expansion gradually erodes forest margins and encroaches on legally protected areas, such as the Okwangwo division of the Cross River National Park.
Commercial logging operations also contribute to habitat destruction by felling trees for timber products. While the direct loss of trees is damaging, the infrastructure logging brings is often more destructive. The construction and improvement of roads to extract timber open up previously sheltered, remote forest areas to human access.
These roads and clearings act as barriers, leading to fragmentation that chops the gorilla’s territory. This prevents gorillas from safely migrating between their 11 known groups, which is necessary for maintaining genetic diversity. The disturbed environment forces the naturally shy gorillas to retreat, shrinking their usable habitat beyond the physical destruction.
Illegal Hunting and Direct Conflict
Direct threats from human activity, particularly illegal hunting, significantly endanger the already fragile Cross River Gorilla population. Although the hunting and killing of gorillas is against the law in both Nigeria and Cameroon, enforcement is frequently insufficient, allowing poaching to continue. Poachers target gorillas for the illegal bushmeat trade, where a single large primate provides a substantial amount of meat.
The small size and slow reproductive rate of the Cross River Gorilla population mean that the loss of even a few individuals to hunting can have a severe impact on the viability of an entire group. Gorillas are also sometimes killed accidentally in snares and traps set for other, smaller animals. This indiscriminate trapping can injure or kill gorillas, further reducing their already critically low numbers.
As human settlements expand and the gorilla’s habitat shrinks, the primates are increasingly forced into closer proximity with people, leading to direct conflict. When natural food sources become scarce due to habitat loss, gorillas may raid nearby farms and crops, prompting retaliatory killings from farmers attempting to protect their livelihoods. Furthermore, this increased contact with humans elevates the risk of disease transmission, as gorillas are susceptible to human pathogens.