Ernie Janes / Black howler (Alouatta caraya) male and female, captive, occurs in Brazil and Paraguay. With digitally added leaf pattern.

Matthew Maran / Delacour's langurs (Trachypithecus delacouri) resting, Van Long Nature Reserve,Ninh Binh, Vietnam. Critically endangered

Yukihiro Fukuda / Japanese macaque (Macaca fuscata fuscata) mother with rare white furred baby, Jigokudani Valley, Nagano Prefecture, Japan. June.

Fiona Rogers / Dusky leaf monkey (Trachypithecus obscurus) baby on a branch . Khao Sam Roi Yot National Park, Thailand. March 2015.

Fiona Rogers / Dusky leaf monkey (Trachypithecus obscurus) juvenile portrait . Khao Sam Roi Yot National Park, Thailand. March 2015.

Anup Shah / Dusky leaf monkey (Trachypithecus obscurus) juvenile yawning . Khao Sam Roi Yot National Park, Thailand. March 2015.

Anup Shah / Dusky leaf monkeys (Trachypithecus obscurus) in tree, one holding baby . Khao Sam Roi Yot National Park, Thailand.

Anup Shah / Dusky leaf monkey (Trachypithecus obscurus) baby playing . Khao Sam Roi Yot National Park, Thailand.

Ole Jorgen Liodden / Golden monkey (Cercopithecus kandti) foraging, portrait, Virunga, Rwanda.

Ole Jorgen Liodden / L'Hoest's monkey (Cercopithecus lhoesti) feeding on leaves, Rwanda.

Ole Jorgen Liodden / Grey-cheeked mangabey (Lophocebus albigena) in Nyungwe NP, Rwanda

Paul Williams / Red leaf monkey (Presbytis rubicunda) mother holding baby, Danum Valley, Sabah, Borneo, Malaysia August.