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Splitjaw Snake: Bolyeriidae

Conservation Status

The World Conservation Union (IUCN) and the U.S. Fish and Wildlife Service consider the Round Island casarea splitjaw to be Endangered, or facing a very high risk of extinction in the wild throughout all or a significant portion of its range. It once lived on the nearby and much larger Mauritus Island, The splitjaw snake has an upper jaw bone split into front and back halves that are hinged together at a point just below the eye. (Illustration by Marguette Dongvillo. Reproduced by permission.) but habitat loss, combined with the presence of non-native species, wiped out the splitjaws. On Round Island, the snakes had to survive the loss of the rainforest. In the 1970s, people became aware of the problems faced by the snakes and other animals on Round Island and set out to remove the non-native goats and rabbits that were eating the native plants, and therefore destroying the soil conditions needed by the snake. Now, to protect the rainforest further, only scientists and conservationists are allowed to visit Round Island. Plans are under way to remove non-native animals from a few other nearby small islands where the splitjaws once lived and possibly release some captive-bred splitjaws there. The hope is that the snakes will survive to breed and produce a wild population.

The U.S. Fish and Wildlife Service lists the smooth-scaled splitjaw as Endangered, but the World Conservation Union (IUCN) lists it as Extinct. No one has seen that species, also known as the Round Island bolyeria boa, since 1975.



Burnie, David, and Don Wilson, eds. The Definitive Visual Guide to the World's Wildlife. New York: DK Publishing, 2001. Page 379.

Day, David. The Doomsday Book of Animals. London: London Editions Limited, 1981.

Greene, Harry W. Snakes: The Evolution of Mystery in Nature. Berkeley: University of California Press, 1997.

Web sites

"Round Island Keel-Scaled Boa (Casarea dussumieri)." http://www.arkive.org/species/GES/reptiles/Casarea_dussumieri/more_info.html (accessed on September 8, 2004).

Additional topics

Animal Life ResourceDinosaurs, Snakes, and Other ReptilesSplitjaw Snake: Bolyeriidae - Physical Characteristics, Geographic Range, Habitat, Diet, Behavior And Reproduction, Conservation Status - SPLITJAW SNAKES AND PEOPLE