Neoteny is the retention of infantile or juvenile characteristics into adulthood. It probably underlies the domestication of many animals and is especially evident in retrievers. Adult domestic animals are more juvenile than their wild ancestors in aggression, lack of fear, tolerance of other animals and humans, etc. Dogs show varying degrees of neoteny: herding dogs like collies are less neotenous and more like adult wolves in the shape of their muzzle and herding behavior, which is essentially hunting and chasing of prey. Retrievers like labs retain a rounded puppy-like face, love to play (retrieve), and are more social and puppy-like in their love of people.
