As its name implies, the Sumatran orangutan – “person (orang) of the forest (hutan)” in Malay – occurs only in forests on the is- land of Sumatra (Rijksen and Meijaard 1999). More specifically, the wild population today survives solely in the north-western regions of the island, in the provinces of Aceh and North Su- matra. Tese provinces stretch from the Indian Ocean in the west to the Strait of Malacca, which separates Sumatra from
mainland Malaysia further to the east. Tey are also bisected by the Bukit Barisan mountain range that runs down the full length of Sumatra.
Tese mountains reach altitudes of over 3,000 meters above sea level (m asl), with the highest peaks being Gunung Ker- inci in West Sumatra (3,800 m asl) and Gunung Leuser