Rhesus monkeys engineered to express a human gene reportedly show delayed brain development and better short-term memory. Fellow scientists are raising ethical red flags.

A combination of public opposition, intense regulations, and rising costs in the EU make conditions in China and elsewhere attractive for studying monkeys.

The stem cell–derived transplants were stable for 24 months and led to wide-ranging behavioral improvements in the monkeys.  

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

Researchers engineered a system for bioluminescent imaging that is as much as 1,000 times stronger than existing methods.

The male proboscis monkey’s large nose probably evolved in response to female preference and competition between males.

Puerto Rico’s Cayo Santiago has hosted decades of research in cognition, primatology, immunization, and other areas.

Meet the people trying to save a research colony of rhesus macaques living on a small island off the coast of hurricane ravaged Puerto Rico.

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