Crab-eating macaque findings. One of the most well known examples of experiments on crab-eating macaques is the 1981 Silver Spring monkeys case. In 2014, 21,768 crab-eating macaques were imported in the United States to be used in experimentation. The crab-eating macaque has the third-largest range of any primate species, behind only humans and rhesus macaques. The IUCN Red List categorizes the species as Least Concern, and CITES lists them as Appendix II ("not necessarily threatened with extinction", in which trade must be controlled to avoid use incompatible with their survival). A recent review of their populations suggests a need for better monitoring
Neoteny in humans lower second and third molars. Populations with a history of dairy farming have evolved to be lactose tolerant in adulthood, whereas other populations generally lose the ability to break down lactose as they grow into adults. Down syndrome neotenizes the brain and body. The syndrome is characterized by decelerated maturation (neoteny), incomplete morphogenesis (vestigia) and atavisms. Neoteny in humans Neoteny in humans is the retention of juvenile features well into adulthood. This trend is greatly amplified in humans especially when compared to non-human primates. Adult humans more closely resemble the infants of gorillas and chimpanzees than the adults. Neotenic features