Will Burrard-Lucas / Tufted gray langur (Semnopithecus priam) Close up portrait of head and shoulders. Minneriya National Park, Sri Lanka. September

Anup Shah / Olive Baboon (Papio anubis) male with three month old young, Gombe National Park, Tanzania

Suzi Eszterhas / Golden Lion Tamarin (Leontopithecus rosalia), Atlantic Forest, Brazil

Suzi Eszterhas / Golden Lion Tamarin (Leontopithecus rosalia), Atlantic Forest, Brazil

Suzi Eszterhas / Golden Lion Tamarin (Leontopithecus rosalia), Atlantic Forest, Brazil

Lucas Bustamante / Toque Macaques (Macaca sinica) Polonnaruwa, Central Province, Sri Lanka

Ernie Janes / Celebes crested macaque (Macaca nigra) infant, captive.

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

John Shaw / Snow monkey or Japanese macaque (Macaca fuscata) female with baby clinging to her back. Jigokudani, Japan, February.

Morley Read / Developing embryo of the Ecuadorian monkey frog (Phyllomedusa ecuatoriana), showing heart beating and blood flowing, Morona Santiago Province, Ecuador, (non-ex)

Bernard Castelein / Rhesus macaque (Macaca mulatta), mixed group of female and juveniles, walking along a track, Keoladeo National Park, Bharatpur, India

Bernard Castelein / Rhesus macaque (Macaca mulatta), juveniles playing in tree, Keoladeo NP, Bharatpur, India