Christophe Courteau / Long-tailed macaques (Macaca fascicularis) grooming, with baby playing nearby, Bako NP, Sarawak, Borneo, Malaysia.

Tony Phelps / Chacma baboon (Papio ursinus) troop exiting den, DeHoop Nature Reserve, Western Cape, South Africa, June.

Neil Aldridge / Vervet monkey (Chlorocebus pygerythrus) yawning while sitting on a fallen tree in forests, Limpopo River, Kruger National Park, South Africa.

Neil Aldridge / Chacma baboon (Papio ursinus) baby riding on top of its mother on the banks of the Chobe River, Chobe National Park, Botswana.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) male showing canine teeth, Qinling Mountains, China.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) juveniles interacting, Qinling Mountains, China.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) females sitting close together with baby inbetween, Qinling Mountains, China.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) female with young suckling, Qinling Mountains, China.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) jumping over a frozen stream, Qinling Mountains, China. Sequence 2 of 7

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) adult male and female hugging, Qinling Mountains, China.

David Pattyn / Zanzibar red colobus monkey (Procolobus kirkii) crossing the main road through the Reserve, Jozani forest, Jozani Chwaka Bay NP, Zanzibar, Tanzania, August.

David Pattyn / Zanzibar red colobus monkey (Procolobus kirkii) portrait in a tree, Jozani forest, Jozani Chwaka Bay NP, Zanzibar, Tanzania, August