Gorilla

Gorillas

Mountain gorillas are among the world's most critically endangered mammals, with three distinct sub-species in equatorial Africa. Fewer than 600 mountain gorilla survive in two isolated populations - some 300 in the Bwindi Impenetrable Forest of eastern Uganda, and a similar number on the slopes of the Virunga volcanoes (shared by Rwanda, Democratic Republic of Congo and Uganda).

In the western tropics, an estimated 30 000 western lowland gorilla survive in the tropical rain forests of the Congo Basin.The bulk of these are found in Gabon where a comparatively low human population exists. No more than several hundred eastern lowland gorilla remain in isolated pockets of forest in the eastern part of the Democratic Republic of Congo. The plight of the gorilla is well-known thanks to the efforts of Dian Fossey (who spent 13 years studying the Virunga population before being murdered in 1985). Others who have raised awareness are George Schaller (who conducted the first scientific study of gorillas in 1959), Ian Redmond and colleagues (who have continued and expanded on Fossey's work in Rwanda and Uganda), and photographer Karl Ammann who has done more than anyone to expose the rampant "bushmeat" trade in West and Central Africa.

Greatest of the Great Apes

The gorilla is one of the so-called "Great Apes" and, along with the chimpanzee, is man's closest relative. It is quite possible that humans, gorillas and chimps had a common ancestor for the trio are said to share around 90% of genetic material. But unlike humans and chimps - who are omnivores that eat fruit and other vegetable matter, as well as meat - the gorilla is almost entirely vegetarian, usually subsisting on a fairly small variety of leafy plant species in their specific environment. The gorilla is the largest of all primates, with males typically weighing between 140 and 160kg (210kg is the record).

Leaves in the Sunlight

Although gorillas are found only in forest habitats, they actually prefer to forage on the sunlit fringes and in clearings where sufficient light allows the large-leaved plants they favour, to flourish. Throughout their range, they appear to like secondary, regenerating forest and it is ironic that their preferred habitat is potentially increased (albeit temporarily) as man makes inroads to forests by logging timber. In reality, gorillas are at grave risk. Exposure to the personnel and transport links associated with logging operations greatly increases the risk of slaughter and capture - primate meat is a delicacy among West Africans.

Gorilla Society

Gorillas live in troops led by a dominant adult male, whose huge physical presence inspires both respect and confidence among the members. The male - which assumes a mantle of silvery-grey hair when about 12, and is then known as a "silverback" - leads the family, deciding where to forage, rest and sleep. A dominant male typically has a harem of three or four mature females, but troops can be much larger. Young females leave the family when adolescent (to avoid breeding with their father) and are sexually mature at about eight years of age. A single infant may be produced at four year intervals, with a gestation period of just under nine months. Babies are usually born under the cover of darkness and although averaging just 2kg at birth, they develop twice as rapidly as humans, able to crawl at three months, for example.

Gentle Giants

Despite terrifying characterisations such as "King Kong", male gorillas are peaceful by nature and make concerted efforts to avoid conflict with rival males in displays of chest-beating, plant-bashing and occasionally charging. Very rarely, a fight may occur. Females and sub-adults are even less demonstrative and go about their daily routine quietly. Other than man, gorillas have few, if any, natural enemies. They do not venture into habitats frequented by lion, and babies are generally too well cared for to be threatened by leopard.

Conservation

There can be little doubt that the most realistic strategy for the survival of remaining gorilla populations is through the setting up of reserves, funded by eco-tourists. Although there have been casualties to both gorillas and their human protectors, it is remarkable that the Virunga mountain gorillas have somehow managed to survive despite Rwanda and the Democratic Republic of Congo being involved in such fierce civil conflict. The few remaining gorilla troops generate such interest and much needed funds that it simply pays to protect them and their remaining habitat. But with expanding human populations in the immediate vicinity and spiralling conflict in the region, it is uncertain how long this tenuous security of the Virunga gorillas will prevail.

The Future

In the Congo Basin, rampant logging - spearheaded by developed European nations - threatens the habitat on which the comparatively high number of lowland gorillas depend. There is an urgent need to develop existing conservation to enable eco-tourists to gain access to the gorillas and contribute to the long-term survival of the diverse rainforest ecosystems. The complexity of gorilla society is such that reintroduction programmes have not been seriously attempted. Such strategies may have to be employed in the future. The UK-based Dian Fossey Gorilla Fund and the French-based ECOFAC are two of the more effective non governmental organisations working to conserve gorillas and their habitats in Africa.

Further Reading
Schaller, G. 1963. The Mountain Gorilla.
   Univ. of Chicago Press, Chicago.
Schaller, G. 1964. The Year of the Gorilla.
   Univ. of Chicago Press, Chicago.
Estes, R. D. 1991. The Behaviour Guide to African Mammals .
   Russel Friedman Books, Halfway House.
Fossey, D. 1983. Gorillas in the Mist.
   Hodder & Stoughton, England.
Kingdon. J. 1997. Kingdon Field Guide to African Mammals.
   Academic Press, London.

Posted: Mammals by CC Africa, Date: 21 November 2006