Ernie Janes / Purple-faced leaf monkey (Semnopithecus vetulus) Sri Lanka.

Lucas Bustamante / Purple-faced langur (Trachypithecus vetulus) holding stick and looking up, Sinharaja, Southern Province, Sri Lanka.

Lucas Bustamante / Purple-faced langur (Trachypithecus vetulus) with wet fur, feeding, Sinharaja, Southern Province, Sri Lanka.

Robin Chittenden / Purple-faced langur (Trachypithecus vetulus) in tree, Sri Lanka.

Robin Chittenden / Purple-faced langur (Trachypithecus vetulus) on branch, Sri Lanka.

Lucas Bustamante / Purple-faced langur (Trachypithecus vetulus) eating on a branch. Sinharaja, Southern Province, Sri Lanka

Nick Garbutt / Purple-faced langur or leaf monkey (Trachypithecus vetulus) in forest canopy. Sinharaja National Park, Sri Lanka.

Ernie Janes / Purple-faced leaf monkey (Trachypithecus vetulus) Sri Lanka, endemic, endangered species.

Ernie Janes / Purple-faced leaf monkey (Trachypithecus vetulus) Sri Lanka, endemic, endangered species.

Sandesh Kadur / Purple-faced langur (Trachypithecus vetulus) Sri Lanka.