During the heightened sexual and aggressive period of musth, males secrete from swollen temporal glands, dribble urine and give a distinctive type of very low frequency call referred to as a musth rumble(1). This call has a characteristically pulsated "put-put-put" quality or may sound like water gurgling through a deep tunnel. Musth rumbling is associated with an increased rate of urine dribbling and a particular ear posture known as ear waving(2).

Males emit musth rumbles in many different, but rather specific contexts including in aggressive and sexual situations, while marking, drinking, or wallowing, as well as in situations where they feel challenged in any way(3). For example, the sound of another musth male, an approaching car, or even an airplane flying over-head is often enough to trigger a male to rumble. Musth males also frequently rumble before or after a bout of listening and presumably in these cases they are either responding to elephant calls that we cannot hear or they are calling and expecting an answer - possibly from potential mates(4).

We do know that when a musth male gives a musth rumble in the company of females he is answered by females with a loud cluster of calls known as a female chorus(5). A musth male is, however, most likely to rumble when he is alone. He rumbles much less when he is in the company of females and even less when he is guarding an estrous female(6). Once he is with an estrous female he may have neither the need nor the desire to advertise his whereabouts to others!

Other males respond differently to the call of a musth male depending upon whether or not they themselves are in musth. A male in musth moves toward the sound of the call while a non-musth male avoiding trouble moves away(7).