Adolescence in the elephant is the time when weaning has stopped until about the age of seventeen. It denotes the period in which final growth and maturation have gone through their greatest changes. Basic herd structures are formed during this time in the life cycle. Another key feature of the adolescent years is the sexual maturity that is reached between the ages of eight and thirteen. This sexual awakening will allow the elephant to breed until the age of fifty. For the male this will mean the onset of musth between fifteen to eighteen years of age; once begun this typically occurs once every year in healthy elephants. The period of musth tends to last around three months, which does not take into account the onset and latter stages.