An elephant's adolescent phase lasts from the time at which it is weaned (completely off mother's milk as a source of nutrition), which can be any time between 5 and 10 years of age, until it is approximately 17.
It is at this important stage that young elephants begin to spend less time with their mothers and to associate with those of their own age, more especially for young bulls / males.
Elephants change the most, physically and emotionally, at this stage. It is also during these years that the basic herd structure is established as young bulls break away from the protective nurturing of their mothers, leaving only the females of the herd behind. Young bulls branch off into bachelor pods, and do not return to the core pod. This break away will typically take place at about 13 years of age, when the bull reaches sexual maturity. Females spend less time with their mothers, but remain with the matriarchal herd, sometimes until they die.
The sexual maturing of elephants is usually complete by 13 years in both sexes. When the males are between 15 and 18 years of age, they experience the onset of musth a thick, black secretion from the temporal glands on the sides of their heads, accompanied by increased levels of testosterone. These increased levels of the male hormone also mean that young bulls tend to have higher aggression levels during this period. The temporal glands swell, causing the bull an immense amount of pain, particularly due to the pressure being exerted on his eyes. This is often evident by the frustrated digging of their tusks into the ground. Musth should take place annually in healthy elephants, and usually lasts for a short period of time.
For the female adolescents, this phase of "puberty" means that their mothering, nurturing instincts are cultivated in response to their hormones. At this age, they are inclined to assist other mothers with their young calves, much like the behaviour of a broody woman. As they are allowed to participate in the rearing of and caring for these babies, they are being trained to look after their own young in the future. This decreases the awkward feelings of ineptitude when they become first-time mothers.
As is the case with humans, adolescence is an exciting time of development as the maturing elephants become an integral part of the herd, while being trained and moulded by their experienced elders.