August 15, 2019
If You Musth Know
Denver Zoo’s Elephants Play a Big Role in Studying a Complicated Hormonal Cycle
By Maura Davis, Elephant Care Expert
If you come to Toyota Elephant Passage, you might see anywhere from one to five of our Asian male elephants together in a given yard. Jake and Chuck might be sparring in one yard while Billy and Bodhi forage in another. Every day brings a new combination for our boys, which is just as fun for their care team to watch as it is for them to socialize. As amazing as it is to watch these boys interact, socializing Asian bull (male) elephants is relatively new, and we’re learning more and more about the intricate social dynamics of this animal every day.
In December of 2016, two years before we welcomed Jake and Chuck, the Toyota Elephant Passage care team started the process of developing a bachelor group. We worked with Billy (8 years old at the time) and Bodhi (12 years old at the time) to become the first two introduced to one another. We were pleased to see how their relationship blossomed and decided to add another bull to the mix. Just a few short weeks later Groucho (46 years old at the time) joined the group under the watchful eye of nearly every person on the elephant care team. All the boys got along great, and we officially had North America’s largest bachelor herd of elephants. At his age and size, Groucho was a natural leader and the dominant bull in the herd. Billy and Bodhi never challenged him and always were submissive when he was around. But the elephant team noticed a big change in the spring of 2017. Billy, our youngest bull, was pushing Groucho around in an aggressive way. This was very unusual behavior that we had not seen from Billy before, especially towards Groucho, and the team worked quickly to separate the group and determine what might have caused this dramatic change in behavior. After careful examination of his behavior over the next couple of days, it was determined that Billy was maturing and had come into his first musth.
Musth is an annual hormonal cycle that naturally occurs in adult male elephants. Their testosterone increases significantly, it has huge impacts on their behavior and they exhibit some physiological changes including draining from their temporal gland on the side of their face as well as continuous urine dribbling down their back legs. Musth is a large part of a male elephant’s life but a lot is still unknown about this cycle. Male Asian elephants are difficult to study in Asia since there are few of them and when they are in musth, they become more aggressive and incredibly dangerous to be around. But here at Denver Zoo, our bulls still participate in training sessions when they’re in musth – which creates an opportunity to learn more about this complicated hormonal cycle. Denver Zoo is participating in a study with researchers Wendy Kiso and Chase LaDue to study musth. This study not only includes male elephants in zoological settings across the United States but also includes male elephants in Sri Lanka.
Bulls: Bullied or Bullies?
Human elephant conflict is a leading cause of elephant population declines Southeast Asia. As human populations grow and the boundary between wild elephants gets smaller and smaller, it’s important for us to understand how musth plays a role in an elephant’s behavior. Musth males often turn towards nutritionally rich foods which typically result in finding their food in human crops. With elevated testosterone levels, those male elephants can be far more aggressive. In Sri Lanka, 70 humans and 235 elephants are dying annually due to human-elephant conflict. Having a better understanding of how musth impacts male elephants’ behavior can give us more information to help environmental management strategies in Asia.
“Elephants in zoos are valuable sources of information for researchers…we can conduct behavioral observations and collect a variety of biological samples with voluntary participation from the elephants. All of this is virtually impossible to do in the field where logistics prevent researchers from following and or approaching elephants. What we learn from elephants in zoos helps us better understand how to study, manage and conserve elephants in the wild,” says LaDue.
Handling the Herd
In June of 2019, more than two years after his first musth, Billy completed his third annual cycle and we now know what to look for in Billy’s behavior that would indicate to us that this hormonal change is occurring. This allows us to set up our herd’s socialization periods appropriately so none of the males are in a situation where there is risk of musth aggression. We have been able to proactively provide an environment where all the males can safely continue to socialize and interact with one another while also accommodating this unique time in a male elephant’s year.
So, the next time you see our five boys at Toyota Elephant Passage, take a minute to appreciate how their interactions are helping people on the other side of the world co-exist with wild Asian elephants! And make sure you stop by one of our daily elephant demonstrations to learn how you can help this endangered species.
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