Neoteny in zoology refers to the slowing or delaying of the physiological or somatic development of an organism, typically an animal, while maintaining constant reproductive development. It is a form of heterochrony that involves the slowing down in a descendant of part or all of its ancestors rate of development, so that at least some aspects of the descendant resemble a juvenile stage of the ancestor. Neoteny can lead to paedomorphosis, which is the retention of juvenile features into adulthood.
In humans, neoteny is the retention of juvenile traits well into adulthood, and it is greatly amplified in humans especially when compared to non-human primates. Adult humans more closely resemble juvenile primates in many ways, such as having a large head, a flat face, and relatively short arms. These neotenic changes may have been brought about by sexual selection in human evolution, and they may have permitted the development of human capacities such as emotional communication.
