Wild elephants seem to address each other using distinctive, rumbling sounds that could be akin to individual names.
That鈥檚 according to a provocative new in the journal Nature Ecology & Evolution, which was inspired by earlier showing that bottlenose dolphins have signature whistles.
鈥淪ometimes another bottlenose dolphin will imitate somebody else's signature whistle in order to get their attention, so effectively calling them by name,鈥� says , a biologist at Cornell University.
He wondered if elephants, which are known to be vocal , might do something similar.
鈥淭he idea from the outset of this project,鈥� says Pardo, 鈥渨as to try to figure out if elephants have names.鈥�
He means names that the animals call themselves 鈥� rather than names like Margaret and Marie that researchers working in nature preserves have given them.
Elephants鈥� trumpeting is well known, but Pardo says trumpeting is an abrupt noise that鈥檚 more like screaming or laughing. He figured that if elephants had names, they鈥檇 be somehow encoded in elephants鈥� constant, low-frequency rumblings.
鈥淭he rumbles themselves are highly structurally variable,鈥� says Pardo, who conducted this research while working at Colorado State University. 鈥淭here's quite a lot of variation in their acoustic structure.鈥�
And elephants make these particular noises in all kinds of contexts 鈥� everything from greeting family members to comforting a calf to staying in touch with relatives over long distances.
So Pardo and some colleagues analyzed recordings of 469 rumbling calls that wild African elephants had made to each other in the Amboseli National Park and Samburu and Buffalo Springs National Reserves in Kenya between 1986 and 2022.
For every recorded call, the researchers knew the identity of the elephant making the rumble as well as, based on the context, the elephant that was being addressed.
If elephants had names, not every call would be expected to contain one 鈥� just like people don鈥檛 use each other鈥檚 names every time they speak to each other.
Still, the research team used machine learning to see if the rumbles contained identifying information 鈥� essentially, a 鈥渘ame鈥� 鈥� that their computer model could learn to use to accurately predict the receiver of a call.
What they found is that their model was able to identify the correct elephant recipient of the call 27.5% of the time, which is much better than it performed during a control analysis that fed it random data, says Pardo.
This indicates, he says, that 鈥渢here must be something in the calls that's allowing the model to figure out at least some of the time who that call was addressed to.鈥�
The researchers then did some field work to see if 17 elephants 鈥� all female except for one 鈥� might recognize their own 鈥渘ames鈥� and react preferentially to recordings that contained those sounds.
鈥淲e had to find a situation where a specific elephant was by herself, or at least not with the individual who made the recording,鈥� he says, explaining that the team would then play the recording through a loudspeaker.
They used different recordings on different days. Depending on the day, the elephant would either hear a recorded call that was originally addressed to her or hear a call made by the same elephant that was not intended for her.
And, it turns out, the elephants generally seemed to know when a rumbling message was actually meant for them, suggesting that it contained something like a name. When they heard those calls, they approached the loudspeaker more quickly. They also vocalized a reply more swiftly, and made more response calls.
鈥淭he elephants responded much more strongly on average to playbacks of calls that were originally addressed to them relative to playbacks of calls from the same caller that were originally addressed to someone else,鈥� says Pardo.
The results of those playback experiments looked 鈥渧ery convincing,鈥� says , a biologist at the University of Texas Rio Grande Valley.
鈥淚 have no doubt that they're addressing them with these, you know, unique labels,鈥� says Berg. 鈥淣ow, are they nicknames? Are they names? Where do they come from?鈥�
Berg wasn鈥檛 part of this research team but has how wild parrot nestlings acquire unique signature calls, aka names, by slightly modifying the signature call of their caregivers.
He notes that in this elephant study, rumbles containing identifying information often seemed to be generated by mothers who were addressing their calves.
鈥淎 good bit of this was between the moms and their calves,鈥� says Berg. 鈥淚t sure seems like they might be getting it from mom.鈥�
So far, though, no one has been able to figure out exactly what acoustic features in an elephant鈥檚 low-frequency rumblings might equate to a name.
鈥淚'd really like to be able to isolate the name of specific individual elephants,鈥� says Pardo, 鈥渂ecause if we could do that, we could answer a lot of other questions that we weren't able to fully figure out in this study.鈥�
It鈥檚 not clear, for example, if elephants all use the same 鈥渘ame鈥� when addressing the same recipient. The researchers also don鈥檛 know if elephants talk about each other in the third person. 鈥淒o they ever use somebody鈥檚 name when they鈥檙e not there?鈥� wonders Pardo.
Berg notes that animals that use name-like sounds 鈥� humans, dolphins, parrots, and now elephants 鈥� all are intelligent, long-lived social animals that live in stable groups.
But that doesn鈥檛 mean that all of these creatures use names in exactly the same ways.
鈥淧eople might assume that elephant names work in exactly the same way as human names, which is not necessarily true,鈥� says Pardo.
After all, he notes, humans and elephants are separated by tens of millions of years of evolution. 鈥淭hat鈥檚 a pretty long time.鈥�
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