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Photo Courtesy of
Perry van Duijnhoven |
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Photo Courtesy of
Perry van Duijnhoven |
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Dr. Ian Singleton and Dr. Gabriella Fredriksson are directing a new orangutan research site in an area known as the West Batang Toru Forest Block in Sumatra. Dr Singleton estimates that there are 400 to 600 orangutans living in this area. Of the 13 identified orangutan populations in Sumatra, only seven are estimated at 250 or more individuals and only four at over 500 individuals. This means that West Batang Toru has one of very few remaining populations with a very high probability of survival under good management. It is also the only potentially viable population wholly within the North Sumatra province, and in addition, represents a possibly unique orangutan population on the island, since years of geographical isolation may have led to distinctive genetic and/or cultural traits.
Great Ape Trust of Iowa support in 2005 allowed Dr. Singleton to help establish a field station and to conduct a more intensive survey of the population and the threats it faces. This in turn will allow more effective management and protection of the orangutans, and will facilitate conservation-useful research on behavior and ecology. Great Ape Trust provided $10,000 in continued support for this work in 2007. Dr. Singleton’s team is making an exhaustive survey of the size and spatial distribution of the orangutan population, primarily by counting nests (all of the great apes make nests for sleeping, providing a clue to their presence even when the apes themselves can’t be seen). They are also habituating the orangutans to the observers’ presence, so they can be observed directly. Females with infants have been seen, indicating that the population is reproducing. Another major task is to identify all of the plant species eaten by the orangutans in West Batang Toru, noting when each species fruits. This allows better understanding of the apes’ movements, activities and dietary preferences. |