Peter Apps in his book Wild Ways1 describes elephant musth beautifully: “Musth (an Urdu word for the rutting behaviour of Asian elephants) is driven by a surge in testosterone, the male hormone.
The signs that an elephant bull is in musth are obvious to both human observers and other elephants. His temporal gland swells up and secretes a sticky fluid that stains the sides of his face. (See photograph by Elizabeth Stene below) He massages the glands with his trunk and rubs them more frequently on trees. He waves one ear – perhaps to waft the smell of his temporal gland secretion towards other elephants. Instead of urinating backwards between his legs with his penis partly extended he continually dribbles urine with his penis sheathed. The urine stains his penis green and splashes onto his hind legs, and it has a powerful odour. He walks with his head high and chin tucked in, his ears tensed and spread. As he walks he swings his head in time with his paces in a definite swagger. He kneels to tusk the ground, and throws logs around.
A bull does not come into musth until he is at least 25 years old. Between 25 and 35 his musth periods lengthen from a few days a year up to one and a half to three and a half months, until at 40 to 50 he is coming into musth for four to seven months each year. As age takes its toll he becomes unequal to the demands he faces and his musth periods shorten and come less often and more irregularly.
A musth bull covers vast distances in his search for sexually receptive cows. Those he finds he guards from other suitors. He becomes extremely aggressive and will vent his feelings on animals other than elephants, and on man and his works.
Elephant cows prefer musth bulls as mates and when she is on heat a cow advertises her condition by the smell of her urine and loud, subsonic calls in order to attract a testosterone-boosted suitor.”