Humans share a large percentage of their genes with monkeys, which makes them vital for all kinds of research. And rhesus macaque monkeys (Macaca mulatta), one of the most iconic Old World species, exhibits remarkably complex cognitive abilities, making them ideal subjects for psychological and behavioral studies.
That’s why the large colony of rhesus monkeys living on a remote Puerto Rican island has proved so important to researchers through the decades.
Most recently, an international team of scientists — including researchers from Yale, Duke, Chicago and Germany’s Leipzig University — has been observing the local population of rhesus monkeys in order to better understand the neural processes key in monkey (and human) decision-making. The research is being led by biologists at the University of Puerto Rico’s Caribbean Primate Research Center, or CPRC.
The monkeys being studied are part of a colony of some 1,200. The population has flourished ever since being brought from India to Cayo Santiago, a small island off the coast of Puerto Rico, 75 years ago. Rhesus monkeys are native to much of southern Asia, but feral populations exist all over the world, including South Carolina and Florida.
Cayo Santiago’s feral colony — which has propagated some 11,000 individuals over 12 generations — is ideal for research as it has remained isolated from other species.
“In fact, this population is unique in the world because we have the purest monkey that can exist since they have not crossbred with any other species,” study leader Angelina Ruiz, CPRC associate director, told EFE.
The monkeys were first brought to the island for biomedical research and they continue to be used for similar purposes. Researchers with the National Institutes of Health continue to rely on the colony for disease-free monkey test subjects — for AIDS studies and other medical research.