[1] Univ Kent, Durrell Inst Conservat & Ecol, Sch Anthropol & Conservat, Canterbury CT2 7NR, Kent, England
[2] Univ Cambridge, Wildlife Res Grp, Sch Anat, Cambridge CB2 3DY, England
[3] Univ Palangka Raya, Orangutan Trop Pearland Project, Ctr Int Cooperat Sustainable Management Trop Peat, Palangka Raya 73112, Central Kaliman, Indonesia
[4] Univ Oxford, Wildlife Conservat Res Unit WildCRU, Dept Zool, Tubney OX13 5QL, Oxon, England
[5] Univ Palangka Raya, Ctr Int Cooperat Trop Peatlands, Palangka Raya 73112, Central Kaliman, Indonesia
[6] Univ Mulawarman, Fac Forestry, Samarinda 75117, East Kalimantan, Indonesia
[7] Queen Mary Univ London, Sch Biol & Chem Sci, London E1 4NS, England