Animal testing on non-human primates between the monkeys natural behaviors versus the behaviors expressed by the diazepam induced monkeys in thirteen different locations inside the maze. Scientist Barros and his colleagues created this model to allow the monkeys to roam a less confined environment and slightly eliminate outside factors that may induce stress. Many of the best-known allegations of abuse made by animal protection or animal rights groups against animal-testing facilities involve NHPs. The so-called "pit of despair" was used in experiments conducted on rhesus macaque monkeys during the 1970s by American comparative psychologist Harry Harlow at the University of Wisconsin–Madison.<ref name="Blum1994/95">Blum, Deborah. "The Monkey
Feral rhesus macaque Feral rhesus macaque Feral rhesus macaques are wild troupes of the rhesus macaque released by researchers, zoos, or private owners, that have been able to survive and propagate in several places in the United States. A research colony was established by the Caribbean Primate Research Center of the University of Puerto Rico on the island of Cayo Santiago, off Puerto Rico. There are no predators on the island, and humans are not permitted to land, except as part of the research program. A colony of rhesus macaques was established around Silver Springs in Florida around the spring of 1938. The