Musth is a periodic condition in male elephants characterized by highly aggressive behavior and increased reproductive hormones. During musth, an elephant's testosterone levels can increase up to 60 times normal levels. Elephants in musth become unpredictable and dangerous as they seek out females in estrus. Proper management of musth elephants requires chaining them securely during this time to prevent potential attacks on humans or other elephants.

3. The musth can be defined as a periodical change of the behaviour of elephant bulls, which can last from some weeks up to some months. This change has got hormonal reasons. In the musth period a bull produces 40 to 60 times more of testosterone (male sex hormone) than in the non-musth time. As far as I know, this phenomenon occurs with elephant bulls only - particularly with Asian elephant bulls.

4. An essential part of the problems of the keeping of elephant bulls is the so-called musth. 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.

5. Some of the males displayed unusual symptoms and characteristics. Some males showed "tears" streaming down the side of their faces (secretions from temporal glands), and continual dripping of urine onto their legs. Besides these physical changes, there were associated changes in behaviour. Males that were streaming tended to follow females that were in oestrus, and were markedly more aggressive than others .

6. Typically, females form groups comprising a number of families consisting of a mother, and her offspring of different ages. These separate and reform depending on current resources. Adult males on the other hand, separate from these family herds, and spend most of their time in the "bull areas", which family groups typically avoid.

7. This is an area, infrequently visited by the breeding herds, where elephant bulls spend much of their leisure time building up strength and sorting out the bull hierarchy; a sort of men’s club. As the bull feels the urge, or the rumblings of an upcoming musth period, he leaves the bull area in search of the herds and any mating opportunities

8. Within bull areas, males encounter each other, and fight over resources such as access to food and water. Bulls establish a dominance hierarchy based on size, with the larger bull being dominant over smaller ones. Musth males are more aggressive probably as a result of higher levels of testosterone, and most other males will avoid a musth bull

10. We are not really sure why elephants enter musth. Individuals that do enter musth manage to exclude all other non-musth individuals from females that are ovulating. This means that they will get to father more offspring and any characteristic or behaviour that allows this will be favoured by natural selection..

12. It is simple to imagine a situation where females stimulated some males to secrete more testosterone. They in turn were more successful at excluding other males from those females because they were much more aggressive, and determined to enter and prolong clashes with other males. This characteristic would quickly spread through the population

65. Brown J.L., Somerville M., Riddle H.S. et al. 2007. Comparative endocrinology of testicular, adrenal and thyroid function in captive Asian and African elephant bulls.General and Comparative Endocrinology 151: 153-162. Abstract: Concentrations of serum testosterone, cortisol, thyroxine (free and total T4), triiodothyronine (free and total T3) and thyroid stimulating hormone (TSH) were measured to assess adrenal and thyroid function as they relate to testicular activity and musth in captive elephants. Blood samples were collected approximately weekly from Asian (n = 8) and African (n = 12) bulls at seven facilities for periods of 4 months to 9.5 years..