Musth is a period among adult male elephants, (over 15-20 years old) sometimes referred to as similar to male deer's "Rot".
(Musth is a word of Persian origin and is translated in the languages of Northern India by "condition of poisoning". The word musth is used to describe an abnormal behaviour or the behaviour of a drunk, whether human being or elephant.)
There is a three weeks pre-musth-condition, about one month high-musth, and one post-musth condition. Their temporal glands become swollen, from where a strong smelling fluid, rich of testosterone, runs down on their cheeks. During musth the males are very aggressive, and sexual active. According to Cynthia Moss, author of the book elephant memories, the older females in a heard gives passage to musth males when a female is in heat, while they block the way for younger males, not in musth. But males are always able to cover a female, also outside the musth period.
The reason for the musth seems to be that it prevents inbreeding. If the bulls would not be at their aggressive peak only for a month a year, only the largest, most dominant bull would cover the females all the time. In captivity, the limited space makes it dangerous to let a bull in musth condition to a female, since she may be attacked and wounded if she is not willing to mate.
Elephant males are able to reproduce from around their eighteenth birthday. However, it would be an extremely unusual event for a bull younger than 30 to mate with a female at the height of her oestrus. At all times there would be at least one large adult musth male with the herd about who would displace any young pretenders. In fact, older bulls that are in musth actually suppress the musth cycle of less dominant younger bulls to the extent that they will fall out of musth a few days. This results in a stable hierarchy of bull elephants, with the older more experienced bulls coming into musth for a full period of three to five months a year, and less dominant bulls being in musth for relatively shorter periods. The most subordinate bulls would be those that have just left the breeding herd, and those will not come into musth at all. Joyce Poole found that Amboseli bulls only enter a sustained period of musth at about 30. Up until then, although they will start musth, and will show a lot of the symptoms, younger bulls will not achieve full musth. A consequence of this hierarchy is that when a bull does actually enter musth he has the experience to cope with the circumstance of being cock-full of testosterone in the presence of a group of receptive females, and in a bunch of like-minded guys. The goal of introducing Kruger elephants to Pilanesberg (and now Hluhluwe-Umfolozi Park) was to establish such a bull hierarchy. This would prevent young males from entering sustained musth until they could manage it.
: The photos from our trip! Overhere! Feel free to use any of these additional letters to correct the spelling of words found in the above post: a-e-t-n-d-i-o-s-m-l-u-y-h-c