African elephants address each other with name-like calls – similar to humans

What’s in a name? People use unique names to address each other, but we are one of the few species known to do so, including bottlenose dolphins. Finding more animals with names and studying how they use them could improve scientists’ understanding of both other animals and ourselves.

As elephant researchers who have spent years observing free-ranging elephants, my colleagues and I wanted to get to know elephants as individuals, creating names for them that help us remember who is who. The elephants in question live completely in the wild and are of course not aware of the names we use for them.

But in a new study published in Nature Ecology and Evolution, we found evidence that elephants have their own names that they use to address each other. This research places elephants among the very small number of species known to address each other in this way, and it has implications for scientists’ understanding of animal intelligence and the evolutionary origins of language.

Finding evidence for name-like calls

My colleagues and I had long suspected that elephants might address each other with name-like calls, but no researcher had tested that idea. To investigate this question, we followed elephants across the Kenyan savannah, recording their calls and, where possible, noting who made the call and to whom the call was addressed.

When most people think of elephant sounds, they think of loud trumpets. But in reality, most elephant sounds are deep, booming sounds known as rumblings that are partially beyond the range of human hearing. We thought that if elephants have names, they most likely pronounce them with rumbles, so we focused on these calls in our analysis.

Elephant rumblings have a deep, sonorous sound. Michael Pardo236 KB (to download)

We reasoned that if rumblings contain something like a name, we should be able to identify who a call is intended for purely based on the properties of the call. To determine if this was the case, we trained a machine learning model to identify the recipient of each call.

We gave the model a series of numbers that described the sound properties of each call and told which elephant each call was directed to. Based on this information, the model attempted to learn patterns in the calls related to the recipient’s identity. We then asked the model to predict the recipient for a separate sample of calls. We used a total of 437 calls from 99 individual callers to train the model.

Part of the reason we had to use machine learning for this analysis is because rumbling conveys multiple messages at once, including the caller’s identity, age and gender, emotional state, and behavioral context. Names are probably only a small part of these calls. A computer algorithm is often better than the human ear at detecting such complex and subtle patterns.

We did not expect elephants to use a name with every call, but we had no way of knowing in advance which call might contain a name. That’s why we included all the rumors that we thought could use names at least some of the time in this analysis.

The model successfully identified the recipient for 27.5% of these calls – significantly better than what it would have achieved through random guessing. This result indicated that some of the rumblings contained information that allowed the model to identify the intended recipient of the call.

But this result alone was not enough evidence to conclude that the rumblings contained names. For example, the model might have picked up the caller’s unique voice patterns and guessed who the recipient was based on who the caller liked most.

In our next analysis, we found that calls from the same caller to the same recipient were, on average, significantly more similar than calls from the same caller to different recipients. This meant that the calls were truly specific to individual recipients, such as a name.

Next, we wanted to determine whether elephants could perceive and respond to their names. To find out, we played 17 elephants a recording of a call originally addressed to them that we assumed contained their name. Then on another day we played a recording of the same caller speaking to someone else.

The elephants made their voice and approached the source of the sound more easily if the call was originally addressed to them. On average, they approached the speaker 128 seconds earlier, spoke 87 seconds earlier, and produced 2.3 times more vocalizations in response to a call intended for them. That result told us that elephants can determine whether a call was intended for them simply by hearing the call out of context.

Names without imitation

Elephants aren’t the only animals with name-like calls. Bottlenose dolphins and some parrots address other individuals by imitating the addressee’s distinctive call, which is a unique “call sign” that dolphins and parrots commonly use to communicate their own identity.

This system of naming by imitation is somewhat different from the way names and other words typically work in human language. Although we occasionally name things by imitating the sounds they make, such as “cuckoo” and “zipper,” most of our words are arbitrary. They have no inherent acoustic connection to what they refer to.

Random words are part of what allows us to talk about such a wide range of topics, including objects and ideas that don’t make any sounds.

Intriguingly, we found that elephant calls addressed to a particular receiver were no more similar to the receiver’s calls than to the calls of other individuals. This finding suggested that elephants, like humans but unlike other animals, can address each other without simply imitating the addressee’s calls.

Two elephants, an adult and a juvenile, stand together in a desert.

Elephants’ use of name-like calls underlines their intelligence. Michael Pardo

What’s next

We still don’t know exactly where the elephants’ names are in a call, or how to tease them apart from all the other information conveyed in a rumble.

Next we want to figure out how to isolate the names for specific individuals. If we achieve that, we can answer a range of other questions, such as whether different callers use the same name to address the same recipient, how elephants get their names, and even whether they ever talk about others in their absence.

Name-like calls in elephants may be able to tell researchers something about how human language evolved.

Most mammals, including our closest primate relatives, produce only a fixed set of vocalizations that are essentially pre-programmed into their brains at birth. But language depends on being able to learn new words.

So before our ancestors could develop a full-fledged language, they had to develop the ability to learn new vocalizations. Dolphins, parrots and elephants have all developed this ability independently and all use it to address each other by name.

Perhaps our ancestors originally evolved the ability to learn new vocalizations to learn names for each other, and later adopted this ability to learn a wider range of words.

Our findings also underline how incredibly complex elephants are. Using random sounds to name other individuals implies a capacity for abstract thinking because it involves using sound as a symbol to represent another elephant.

The fact that elephants must name each other in the first place underlines the importance of their many different social bonds.

Learning about the minds of elephants and its similarities to our own can also increase people’s appreciation for elephants at a time when conflict with humans is one of the greatest threats to the survival of wild elephants.

This article is republished from The Conversation, an independent nonprofit organization providing facts and trusted analysis to help you understand our complex world. It was written by: Mickey Pardo, Colorado State University

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Mickey Pardo has received funding from the US National Science Foundation.

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