Andrew Walmsley / Sumatran orangutan (Pongo abelii) mother and baby Bukit Lawang, North Sumatra.

Jabruson Motion / Conservation workers carrying a sedated Sumatran orangutan (Pongo abelii) towards vehicles and a transport box, part of a relocation programme, Sei Serdang, Prima, Batang Serangan, Langkat, North Suma...

Tim Fitzharris / Sumatran Orangutan (Pongo abelii) male, native to Sumatra

Ingo Arndt / Sumatran orang utan feeding on termites {Pongo pygmaeus abelii} Sumatra, Indonesia

Ingo Arndt / Orang utan hand holding branch close-up {Pongo pygmaeus abelii} Sumatra, Indonesia

Cyril Ruoso / Sumatran orangutan (Pongo abelii) baby reaching up to mother's hand, Gunung Leuser National Park, Sumatra, Indonesia.

Cyril Ruoso / Sumatran orangutan (Pongo abelii) female holding hands with baby whilst hanging from liana. Gunung Leuser National Park, Sumatra, Indonesia.

Hiroya Minakuchi / Sumatran Orangutan (Pongo abelii) juvenile playing with branch, native to Sumatra

Jabruson / 'Kith' / 'Kin' Sumatran orangutan (Pongo abelii) captive animal in walled enclosure, Perth Zoo, Western Australia, August 2001.

Fiona Rogers / Sumatran orangutan (Pongo abelii) female 'Sandra' aged 22 years portrait. Gunung Leuser National Park, Sumatra, Indonesia. Apr 2012. Rehabilitated and released (or descended from those which were rele...

Fiona Rogers / Sumatran orangutan (Pongo abelii) female 'Pesec' aged 28 years portrait. Gunung Leuser National Park, Sumatra, Indonesia. Apr 2012. Rehabilitated and released (or descended from those which were relea...

Fiona Rogers / Sumatran orangutan (Pongo abelii) mature male 'Halik' aged 26 years lying down - portrait. Gunung Leuser National Park, Sumatra, Indonesia. Apr 2012. Rehabilitated and released (or descended from thos...