Nearly 50 years after its development, only a handful of creatures have passed the self-awareness exam. A new attempt with fish highlights a debate over the test’s use and meaning.

The function of early hominins’ enlarged brow ridges, and their reduction in size in Homo sapiens, have puzzled paleoanthropologists for decades.

A study finds two species of guenon monkeys in Tanzania have been mating and producing fertile offspring for generations.

The approach, which has never before been successfully attempted in primates, could lead to improved animal models for human biology and disease.

The Tapanuli orangutan has been identified as the newest species of great ape, but also likely the most endangered. 

The results of a historical primate behavior analysis suggest that species with fruit-filled diets evolved larger brains.

The newly identified Skywalker gibbon (Hoolock tianxing) is threatened with extinction, along with roughly 60 percent of primate species worldwide.

The findings suggest language may have started to evolve millions of years earlier than once thought.  

Wild capuchin monkeys in Brazil produce sharp stone flakes by accident, causing some researchers to suggest a rethink of the beginnings of human tool use.