Are the gorillas in Uganda’s Bwindi Impenetrable National Park “true” mountain gorillas?

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Primate taxonomists have been arguing for years that the Bwindi gorillas are not true mountain gorillas!

UNESCO‘s list of world heritage sites includes the following for Uganda:

As stated in the Encylopedia of Earth (a great source of well researched information):  “Bwindi Impenetrable National Park (1°07’S x 29°65’E) is a World Heritage Site located in south-western Uganda at the junction of the plain and mountain forests. The area covers 33,000 hectares (ha) and is known for its exceptional biodiversity, with more than 200 species of trees, over 100 species of ferns, more than 350 birds and over 200 butterflies, as well as many endangered species, including the mountain gorilla.”

It turns out that some primate taxonomists have been arguing for years that the Bwindi gorillas are not true mountain gorillas!

Sarmiento E, Butynski T, and Kalina, J from the Department of Anatomy, Makerere University, Kampala, Uganda, and Department of Mammology, American Museum of Natural History, New York City published, in 1996, a paper stating that “Based on their geographic proximity to the Virunga Volcanoes ( 25 km), the Bwindi-Impenetrable Forest gorillas have been referred to the subspecies Gorilla gorilla beringei. Differences in anatomy, habitat, ecology, and behavior, however, suggest Bwindi gorillas are distinct from those in the Virungas. Relative to Virunga gorillas, Bwindi gorillas live at lower elevations, in warmer temperatures, are much more arboreal, have longer day ranges and larger home ranges, and eat much more fruit and pith, and less bamboo and leaves. Morphological differences reflect the differences in ecology, habitat, and behavior. Bwindi gorillas measured have smaller bodies, relatively longer limbs, hands, and feet, shorter trunks, thumbs, big toes, and tooth row lengths, and narrower trunks and orbital breadths than Virunga gorillas. These differences indicate Bwindi gorillas do not belong to G.g. beringei and should not be referred to as mountain gorillas.”

But before you pass on this great location because of this controversy, let me assure you that modern methods have now resolved this. Taxonomists use a number of morphologic criteria to distinguish between subspecies of gorillas. Ironically, in the same year as the Sarmiento publication, Karen J. Garner and Oliver A. Ryder from the Center for Reproduction of Endangered Species, Zoological Society of San Diego, San Diego, California publshed an elegant study using mitochondrial DNA sequencing and pronounced “Two currently isolated populations of mountain gorillas, one in the Virungas Volcanoes region and the other in the Bwindi Forest, are indistinguishable using this mitochondrial DNA region for comparison.”

A very recent(2010) publication by Alison A. Elgart from the Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, Florida, showed by morphologic methods and rigorous statistical analysis that “Results indicate that the Bwindi gorillas have generally smaller crania than the Virunga gorillas, but when metrics are log-transformed, the only variable that distinguishes the Bwindi individuals is a longer face. When both populations are compared to G. g. graueri, they cluster together separately from the eastern lowland gorillas, sharing such features as higher rami, wider bigonia, longer mandibles, and wider and shorter mandibular symphyses in relation to G. g. graueri. Functional morphological explanations for these differences are discussed, but lacking measurements of the physical properties of G. g. graueri, they cannot fully be explained. Results clearly indicate that at least pertaining to the cranium, upon which most gorilla taxonomy is based, the Bwindi gorillas are proper mountain gorillas (G. b. beringei)”.

The Bwindi gorillas no longer need to be embarassed by this name calling!

You should visit this World Heritage Site to see these magnificient primates. It will be an unforgettable experience. A useful site for planning your trip is the Uganda Wildlife Authority’s website which will provide details about permits which must be obtained well before your trip begins.

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