Neoteny

Neoteny is the retention of juvenile characteristics by an organism that has developed to sexual maturity.

Examples[edit]

The most famous neotenous organism is probably the axolotl which retains the form of a larval salamander throughout its life, but which can be artificially induced to metamorphose by stimulation of the thyroid gland.

The body proportions of many ratite birds, such as the ostrich and emu, remain the same in adults as in chicks, and their plumage remains soft and fluffy like the down of a chick.

A number of biologists, notably Stephen Jay Gould, have speculated that humans, with sparse hair and enlarged heads, resembling juvenile primates, are also neotenous organisms.