The demands of traditional Asian medicine (TAM) don't just pose a threat to the survival of tigers and rhinos (Nature 480, S101–S103; 2011). Numerous smaller species are also at risk, as a result of being traded in large volumes. (Correspondence)

This report presents an assessment of the trade in gibbons and orang-utans in Sumatra, Indonesia, including the islands off Sumatra’s west coast (most notably, the Mentawai Islands). Until recently Sumatra and its off-lying islands harboured one of the largest expanses of lowland evergreen rainforest in Southeast Asia.