Habitat loss and hunting are among the primary threat factors for the animals on the list.
These ocular show-offs really bring the visual razzle-dazzle.
These often solitary great apes with soulful eyes can look like philosopher-kings.
A group of smuggled apes were repatriated, five years after the majority of them were discovered abandoned by the side of the road.
Nicolas, a tufted capuchin monkey, gets help at a primate treatment center.
The smaller the testes in a howler monkey species, the larger the size of the animal's hyoid bone, which enables the monkeys to make booming calls.
The first five monkeys were released in early September, a key moment in a program that has been in the works since 2010.
The primate with serious language skills gets a special present for her 44th birthday.
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