Wednesday, July 1, 2015

Mountain Gorillas Information -Rwanda

Mountain Gorillas Information -Rwanda

The most celebrated resident of Virunga Mountains is the Mountain gorilla, distinguished from other forms of gorilla by several adaptations to its high altitude home, most visibly a longer and more luxuriant coat. Approximately 300 mountain gorillas live in the Virungas, with their total range of 420km spread across three countries: Rwanda, Uganda and the DRC. Current estimates place Rwanda’s & DRC’s gorilla population at around 300 plus (being approximately 50%), about half of which move in two large groups of between 30 and 40 individuals, and the remainder in smaller groups of between five and 15 animals. While European biologists first described the lowland species of gorilla in the mid-18th century, the mountain gorilla was unknown to Western science until 1902, when two individuals were shot in the Virunga Mountains by Oscar van Beringe.

The first detailed study of wild mountain gorilla behaviour was undertaken in the 1950s by George Schaller, whose pioneering work formed the starting point for the most recent and better-publicised study done by late Dian Fossey in Rwanda. Mountain gorillas are on the average bulkier than other species of gorilla, weighing up to 200kg, though the heaviest individual gorilla recorded is a 210kg Eastern Lowland gorilla measure in DRC (Zaire). Like other gorillas, they are highly sociable, moving in defined troops of anything from five to 50 animals. A troop typically consists of a silverback male [males back turns silver when he reaches sexual maturity at about 13 years old], his three or four “wives” and several young animals. Unusually for mammals, it is the male who forms the focal point of a troop; when he dies, the troop disintegrates.

A silverback will start to acquire his harem at about 15 years of age, normally by attracting a young sexually mature female from another troop. He may continue to lead a troop well into his forties.

Female gorillas reach sexual maturity at the age of eight, after which they often move between troops several times.

However, once a female has successfully given birth, she will normally stay with the same silverback until he dies, and she will even help defend him against other males [if a male takes over a troop, he will kill any nursing infants which are not his, a strong motive for a female to help preserve the status quo]. A female gorilla has a gestation period similar to that of a human, and if she reaches old age she will typically have raised up to six of her offspring to sexual maturity. A female status within a troop is based on the length of time she has been with a silverback; the longest serving member of the harem is normally the alpha female.

Mountain gorillas have a primary vegetation diet, and are known to eat 58different plant species. Gorillas also eat insects, with ants being a particularly popular protein supplement. A gorilla troop will spend most of its waking hours on the ground, but it will generally move into the trees at night, when each member of the troop builds itself a temporary nest. Gorillas are surprisingly sedentary creatures. Typically moving less then 1km in a day, which makes tracking them on a day-to-day basis relatively easy for experienced guides. A troop will generally move a long distance only after a stressful incident, for instance an aggressive encounter with another troop.

Gorillas have few natural enemies and they often live for up to 50 years in the wild, but their long-term survival is critically threatened by poaching, deforestation and increased exposure to human-borne diseases. Unlike their lowland cousins, mountain gorillas have never been reared successfully in captivity. Dian Fossey’s “Gorillas in the Mist” is a good [see Further Reading] is a good starting point for anybody who wants to know more about mountain gorilla behaviour.

Visiting the gorillas in Rwanda

Mountain gorilla tracking in the Virungas is a peerless wildlife experience, and one of Africa’s indisputable travel highlights. It is difficult to describe the simple exhilaration attached to first setting eyes on a wild mountain gorilla. These are enormous animals: the silverbacks weigh about three times as much as the average man, and their bulk is exaggerated by a shaggily luxuriant coat. And yet despite their fearsome size and appearance, gorillas are remarkably peaceful creatures, certainly by comparison with most primates – gorilla tracking would be a considerably more dangerous pursuit if these gentle giants had the temperament of vervet monkeys, say, baboons [or for that matter, humans].

More impressive even then the gorilla’s size and bearing is their unfathomable attitude to their daily human visitors, which differs greatly from that of any other wild animal.

Anthropomorphic as it might sound, almost everybody who visits the gorillas experience an almost mystical sense of recognition: we regularly had one of the gorillas break off from chomping on bamboo to study us, its soft brown eyes staring deeply into ours, as is seeking out some sort of connection.

Equally fascinating is the extent to which the gorillas try to interact with their visitors, often approaching them, and occasionally touching one of the guides in apparent greeting as they walk past. A photographic tripod raised considerable curiosity with several of the youngsters and a couple of the adults – one large female walked up to the tripod, stared ponderously into the lens, then wondered back off evidently satisfied. It is almost as if the gorilla recognise their daily visitors as a troop of fellow mates, but one too passive to pose any threat – often a youngster would put on a chest- beating display as it walked past us, safe in the knowledge that we’d accept its dominance, something it would never do to an adult gorilla. It should be here that close contact humans can expose gorillas to fatal diseases, for which reason the guides try to keep the tourists at least five meters away – but the reality is that there is little anybody can do can stop the gorillas from flouting rules of which they are unaware.]

The magical hour with the gorillas is relatively expensive and getting there – have no illusions – can be hard work. The hike up to the mountain gorillas’ preferred habitat of bamboo forest involves a combination of steep slopes, dense vegetation, slippery underfoot conditions after rain and high altitude. For all that, the more accessible gorilla groups can be visited by reasonable fit adults of any age, and in 15 years of African travel we have yet to meet anybody who has gone gorilla tracking and regretted the financial or physical expenses.

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