The island of Cayo Santiago lies off the coast of Puerto Rico and is home to a free-ranging rhesus macaque colony. This colony was initially established in 1938 for behavioral observation. Research focuses on questions of behavior, cognition, communication, morphology, and physiology. The field station hosts a number of short-term projects, but also maintains a database of information on individuals from 1957 to the present day. This database allows researchers to explore longitudinal questions concerning social behavior, morphology, physiology, and genetics.