The Center maintains colonies of approximately 3,800 rhesus monkeys, 335 Japanese snow monkeys, 10 vervets, 9 baboons and 85 cynomolgus macaques.
The founding troop of rhesus monkeys, whose natural range is from northern India to northern China, was brought to Brown University in the 1950’s and transferred to Oregon in 1964.
In the same year, the government of Japan sent a troop of 46 snow monkeys to the Center for conservation purposes—they are threatened by deforestation and by farmers who treat them as pests—and so that scientists could study their behavior and social organization. Some 1700 snow monkeys have been born at the center, most of which now live in zoos and recreational parks in North America.
In 2003, the Center added vervets to its colony. Originally found in Africa or Asia, these monkeys were raised on the Caribbean island of St. Kits.
The Center is also the home of 10 juvenile male baboons. They are part of a study on hemostasis and blood coagulation mechanisms that are active in heart disease. The olive baboon, Papioanubis, is native to Central Africa. Its habitat ranges from grassland steppe to tropical rain forests. Baboons eat plants, grasses, mushrooms, invertebrates, and small vertebrates up to and including gazelles. Baboons form matrilineal lines, like rhesus, but unlike rhesus the males will raise their offspring if the mother dies. Baboons communicate using a series of barks, yaks and grunts. They will yawn to reveal their canines when threatened. They also lip smack for reassurance and spend time grooming each other to remove parasites and dead skin.