Elephants seem to invent names for each other

Elephants may be the only animals besides humans to come up with arbitrary names for each other, according to an analysis of recordings using machine learning.

The analysis found that some calls from African savannah elephants (Loxodonta africana) seem to contain name-like components specific to certain individuals. What’s more, those individuals know their names, responding more strongly than others do when calls addressed to them are played back on a speaker.

“I had noticed from years back that when an elephant gave a contact rumble, within a group of elephants I would see one individual lift its head, listen and give an answer,” says Joyce Poole at ElephantVoices, a small organisation that studies elephants and aims to protect them. “And the rest seemed to just ignore the elephant. So I did wonder whether the calls were being directed toward a specific individual.”

More than 600 recordings made by Poole and others have now been analysed by Michael Pardo at Colorado State University and his colleagues. The recordings included contact rumbles, made when the recipient is out of sight, and greeting rumbles, made when one elephant approaches another. The researchers knew which individuals were calling and responding in each case.

In a quarter of cases, the software created by the team was able to predict which individual was being addressed, a result significantly better than chance.

The researchers then played back some of the rumbles to pairs of elephants, including the “named” individual. They found that the named elephant responded more strongly: they approached the speaker faster, made calls in response faster and also made more calls altogether than the other, unnamed individual.

Dolphins and several species of birds have been shown to call to specific individuals by imitating the sound made by the animal they are calling. However, while Poole reported in 2005 that elephants can learn to mimic sounds, the team found no evidence that the elephants were mimicking each other.

In other words, they seem to be using arbitrary sounds as names, just as humans do, says Poole.

What the analysis didn’t reveal is whether different elephants share the same name for one specific individual. It could be that each elephant has its own set of names for others.

“With us, we have formal names, but different individuals may refer to the same person with different nicknames,” says Poole. “So it may be something like that. I don’t think we know yet.”

“This is a super interesting study with multiple lines of evidence suggesting that African elephants not only produce individually specific vocalisations – which is commonly reported in many species – but more importantly respond specifically when they hear their own individually specific vocalisation given by another elephant,” says Daniel Blumstein at the University of California, Los Angeles.

“The idea that elephants can use individually specific vocalisations to attract specific individuals is novel, exciting and opens the door to a much more nuanced understanding of the rich social lives that these animals have,” he says.

“I find the results quite plausible,” says Thorsten Balsby at Aarhus University in Denmark.

Balsby studies parrots that live in much larger groups. He points out that in large populations with hundreds or thousands of individuals, learning names would be very difficult. “Addressing other individuals by imitation is a simpler solution that does not require prior interactions,” he says.

A 2005 study reported that green-rumped parrotlets kept in captivity “vocally labelled”, or named, their companions, says Balsby. But they did so with different versions of their contact call. “So it might not be quite as arbitrary as the elephants,” he says.

Poole thinks her study is just the beginning when it comes to understanding elephant communication. “There are layers of complexity in elephant communication that are going to take some time to unravel, so I think we’ll have lots more exciting discoveries in the years to come,” she says.

For instance, she suspects elephants might use place names too. “When they’re giving their ‘let’s go’ rumbles, where they indicate the direction they want to go to other individuals in the group, they might actually be saying precisely where they want to go,” says Poole.