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
Crab-eating macaque durians such as "Durio graveolens" and "D. zibethinus", and are a major seed disperor for the latter species. Although the species is ecologically well-adapted and poses no threat to population stability of prey species in its native range, in areas where the crab-eating macaque is not native, it can pose a substantial threat to biodiversity. Some believe the crab-eating macaque is responsible for the extinction of forest birds by threatening critical breeding areas as well as eating the eggs and chicks of endangered forest birds. The crab-eating macaque can become a synanthrope, living off human resources. They are known to