On the Amboseli plains, the boys are back in musth

It takes a lot of vegetation to build a body that may weigh five or six tonnes.

It’s that time of year again.

After the rains, in addition to potholes and muddy spots, elephant researchers in Amboseli need to keep a look out for musth males.

Musth is the sexually active state adult male elephants enter in order to compete for females. While most of the Amboseli males are relaxed even when in musth, this is a period of intense competition for them, and we usually prefer to maintain a respectful distance.

Elephants are sexually dimorphic; an adult male is more than twice the size of an adult female and can grow in body size and bulk well into his forties.

Therefore, they follow different ecological strategies. For example, while females must drink every day to assure their milk production, males can stay in drier areas, reducing the energy and time spent travelling. The heart of Amboseli is a female area, so we often only see males when they come back to check out which females are available to mate.

Sexual dimorphism is an evolutionary signal of intense male-male competition: When you consider that any female is only available to conceive for 3-5 days every 3-5 years, you begin to understand how rare the opportunities are for male elephants to pass on their genes.

Young male elephants leave their family when they’re teenagers, striking out on their own to become established in male society. Friendships are very important to males, especially while they learn about other males and find their way around new areas. Like females, males build friendships over time. These can last lifetimes, and males are especially affectionate with their friends.

Young males must build relationships outside their family. Here, Jeremy from the JA family plays with Kristian, who is fourteen years older.

All males are attracted to the oldest, largest males, who are often accompanied by a group of younger males. Just as family units depend on the accumulated knowledge of older females, old males dominate society and keep younger males “in line.” Females also prefer mating with experienced older males, who have both good genes and good manners, guarding females until they are in peak oestrus. (This is in sharp contrast to overexcited younger males, who tend to harass and hassle females before they are ready to mate.)

Males must wait many years before they have good mating opportunities. Because fights are risky and can be fatal, male elephants have a whole suite of behaviour to evaluate the size, attitude and dominance status of competitors. Young males start this early with wrestling games, or playfully shoving each other as they travel side by side.

Males become very good at assessing size. Sometimes they seem keen to point that out to elephant researchers, too.

Males start entering musth when they are in their late twenties, or early thirties. Although males can father calves at any time, during musth males are advertising their willingness to compete (i.e. fight for) access to females, and showing females how strong and healthy they are. These signals operate through sight, smell and sound. Even humans can spot a musth male a mile off; they walk with chin tucked in to display their height and a rolling swaggering gait that shows off their bulk.

They secrete thick fluid from their enlarged temporal glands and dribble urine, filling the air with their hormones, and leaving a scent trail behind them. Males also have a special musth rumble.

Musth is an “honest” evolutionary signal because males can’t fake it – they must be strong and healthy to enter and maintain it. Musth involves metabolic changes too; very high circulating testosterone burn calories faster. Males also travel further during their musth period, and spend less time feeding. Overall, therefore, musth males steadily lose body condition and can only maintain musth for a few months at a time, even if they don’t get injured in fights.

The phenomenon of musth lets males manage intense competition effectively. It’s another example of the complexity and flexibility of elephant social lives. Males who are friends with one another don’t come into musth at the same time, so they avoid competing directly and risking important relationships.

It’s a fascinating part of elephant biology and behaviour. But for elephant researchers, the take home message is deeply practical: show respect when the big boys are cruising for girls and making trouble with their peers.


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Céline Sissler-Bienvenu, Director, France and Francophone Africa
Director, France and Francophone Africa
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