Imagine a group of bull elephants gathered around a waterhole in the cool evening.
After some time, a senior male lifts his head, flaps his ears gently, and lets out a deep, resonant rumble.
One by one, the other elephants respond, creating a chorus of low-frequency sounds that whisper across the savanna. This elephant “barbershop quartet” is signaling that it’s time to move on.
For the first time, scientists from Stanford University and other institutions have documented male elephants using these “let’s go” rumbles to coordinate group departures at the Mushara waterhole in Etosha National Park, Namibia.
This behavior was previously thought to be exclusive to female elephants in family groups.
“We were surprised to find that male elephants, who are usually considered to have loose social ties, engage in such sophisticated vocal coordination,” said study lead author Caitlin O’Connell-Rodwell, a research associate at Stanford University’s Center for Conservation Biology.
“These calls show us that there’s much more going on within their vocal communication than we previously knew.”
The research, published in the open-access journal PeerJ, involved a 20-year project. O’Connell-Rodwell first recorded the male “let’s go” rumble in 2004 while studying how elephant vocalizations travel through the ground at night.
“It was thrilling to realize that these males were using complex vocal coordination just like the females,” she recalled.
From 2005 to 2017, the team gathered data at the Mushara waterhole during the dry seasons. They used high-tech recording equipment, including buried microphones and night-vision video cameras, to capture the infrasonic vocalizations and behaviors of male elephants. These sounds are too low for human ears to hear.
The researchers analyzed the vocalizations for acoustic properties and patterns and used social network analysis to understand relationships and hierarchy among the males. They noted which elephants initiated the rumbles, how others responded, and the sequence of events leading to the coordinated departures.
The “let’s go” rumbles observed in male elephants are similar to those previously recorded in female elephants. The researchers believe that male elephants learn this behavior when they are young, growing up in families where female leaders use this ritual. As they mature and form their own groups, they adapt and use these learned behaviors to coordinate with other males.
The initiator’s call is followed by the next individual’s rumble, with each elephant waiting for the preceding call to almost finish before adding their own voice. This creates a harmonious, turn-taking pattern like a barbershop quartet.
This study builds on previous research that used AI to show that wild elephants have unique names for each other, indicating the use of nouns in their communication. “In our paper, we show that elephants are using verbs in the form of this ‘let’s go’ rumble. If they are using noun-verb combinations together, that is syntax. That is language,” O’Connell-Rodwell said.
The study also reveals that some dominant male elephants play crucial roles within their social groups, helping to maintain cohesion and stability. These older males take on mentoring roles, guiding and sharing resources with younger elephants.
In countries that allow hunting, care should be taken to avoid hunting older, socially connected male elephants, as their removal could disrupt social cohesion and mentoring structures within elephant populations. The research highlights the importance of strong social bonds and interactions for the well-being of captive and semi-captive male elephants.
“Our findings underscore the complexity and richness of the social lives of male elephants,” O’Connell-Rodwell said, “and advance our understanding of how they use vocalizations in ritual and coordination, bringing us closer to the idea of elephant language.”
