When people talk about the great apes, most of them probably think of the mountain gorillas that Dian Fossey made famous. The incredible work that she did in Rwanda’s Virunga mountains, as well as her unsolved murder, captured the West’s imagination. This accounts for a good deal of the mountain gorilla’s popularity as a tourist attraction – they are probably the most photographed apes in the world. But the truth is they are a subspecies of a much larger and varied gorilla population. All in all there are two species of gorilla (Eastern and Western) with two closely related subspecies in each:

Eastern Gorilla (Gorilla beringei)

Eastern lowland gorilla (Grauer’s gorilla). Population: 2,000-5,000

640px-Gorillas_in_Uganda-1,_by_Fiver_Löcker - 2
Read more about the eastern lowland gorilla

Mountain gorilla. Population: less than 900

Read more about the mountain gorilla

Western Gorilla (Gorilla gorilla)

Western lowland gorilla. Population: Uncertain – less than 95,000

Read more about the western lowland gorilla

Cross River Gorilla. Population: 200-300

Read more about the Cross River gorilla

Map source: IUCN


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The Ebola Factor

It is estimated that a quarter of Africa’s gorillas have died from Ebola in the last 12 years.
The decline in western lowland gorilla populations led to a change in their conservation status from “endangered” to “critically endangered” in 2007. It is estimated that the total western lowland gorilla population in Odzala-Kokoua National Park dropped from 42,000 to 20,000.
In 2002 an Ebola outbreak killed 130 of the 143 western lowland gorillas primatologist Magda Bermejo had been working with in Republic of Congo’s forests, along with thousands of other primates and humans. Click here to read more about the gorillas with whom Magda works (Takes you to another page in this magazine)
A 2004 Ebola outbreak killed up to 95 percent of the western lowland gorillas that frequented Lokoué forest clearing in the Odzala-Kokoua National Park.
The Ebola virus does not threaten other apes and chimpanzees with extinction, but it has reduced the western lowland gorilla population to a point where it can no longer sustain itself in the face of hunting, loss of habitat and other influences. Gorillas breed slowly, and optimistic estimates predict it would take the population 75 years to recover from its present situation. Most of the gorillas that survived are young males, meaning the social structures changed and smaller groups predominated. This affects the normally strong sense of social cohesion and protection found in larger groups. This also makes them more susceptible to stress brought on by poaching.
It is understood that the Ebola outbreaks in human populations often come about from eating the bushmeat of primates infected with the disease.

Bushmeat and the influence of Logging

The commercial logging of Congo’s forests has a direct impact on gorillas, not through loss of habitat as one would think, but due to the pressure from poaching for bushmeat.
The dense, road-less forests made hunting access extremely difficult in Republic of Congo and gorilla densities were high. Since the 1980’s improvements in transportation infrastructure, devaluation of the regional currency, declining oil stocks, and timber depletion in other tropical regions have led to an explosion in mechanised logging in the forests.
Calculations are that timber production nearly doubled between 1991 and 2000. Previously inaccessible forests have been penetrated by logging roads, providing commercial hunters access to previously inaccessible areas with high ape densities. Much of the bushmeat is transported to commercial markets on logging vehicles, and logging employees eat more bushmeat than the local villagers do. This encourages villagers to hunt commercially, selling bushmeat to loggers.

Gorilla Habituation

Aside from the benefit of tourism revenue which is directed to the conservation of gorillas, habituation is vital for proper research by scientists. An equally important factor is the education of tourists, journalists, politicians and students. Guillaume Le Flohic, African Parks manager of conservation and research in Odzala-Kokoua National Park, is running a new gorilla habituation program working with primatologist Magda Bermejo and a few other scientists.
“The work before the habituation process – tracking and monitoring a group to the point where we can walk with the group and observe them from a few meters without changing their natural behaviour – is the most challenging because it depends on several factors,” says Le Flohic:
• The right area – not too many insects or swamps, and with ease of access.
• The right population – large enough, not too affected by poaching which has an aggravating effect on gorilla behaviour and stress levels. The more stressed they are, the more risky it becomes for the habituation team.
• The right group – the dominant male (the silverback) must be quiet and not too aggressive by nature.
• Good human resources – trackers, managers and scientists.

One of the most important aspects of habituation is tracker training. Many trackers are recruited from the local population and the skills they use for hunting can be put to good use. “Trackers need to process a lot of information in a short time, and ex-hunters understand the work in the field very quickly,” says Le Flohic. “I recruit young and old hunters, so the young can benefit from the elders experience and be the future “scientific” trackers – being trained and taught to see the forest they know through scientific eyes.”africa-geographic-logo


Sources: International Union for Conservation of Nature (IUCN); World Wildlife Fund (WWF); National Primate Research Center, University of Wisconsin – Madison.

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