Sumatran orangutans are even more endangered than their Bornean counterparts, with numbers in the wild estimated at under 8,000. They are only found in the forests of the Indonesian island of Sumatra, and are the largest of the tree-dwelling primates. They rarely venture out of the canopy where they build nests to sleep or nap in. A large appetite for fruit makes these primates very important to forest ecology as dispersers of seeds.

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