by What’s in a name? Humans use unique names to address each other, but we’re not one of the handful of animal species we know, including bottlenose dolphins. Finding more animals with names and investigating how they use them can improve scientists’ understanding of other animals and ourselves.
As elephant researchers who have observed free-ranging elephants for years, my colleagues and I get to know wild elephants as individuals, and we make up names for them that help us remember who is who. The elephants in question live entirely in the wild and, of course, do not know what epithets we apply to 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 interact in this way, and has implications for scientists’ understanding of animal intelligence and the evolutionary origins of language.
Look for evidence for calls like names
My colleagues and I had suspected for a long time that elephants could address each other with calls similar to names, but no researchers had tested that idea. To investigate this question, we followed elephants across the Kenyan Savannah, recording their speech and noting, where possible, who made each call and to whom the call was directed.
When most people think of elephant calls, they imagine loud trumpets. But in reality, most elephant calls are deep, muffled sounds called rumbles that are partially within the range of human hearing. We thought that if elephants have names, they are more likely to say them in fruit, so we focused on these calls in our analysis.
An elephant’s rumble has a deep, melodious sound. Michael Pardo236 KB (download)
We reasoned that if a rumble contains something like a name, we should be able to identify who a call is intended for based on the properties of the call alone. 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 it which elephant each call was directed at. Based on this information, the model tried to learn patterns in the calls related to the identity of the recipient. Next, we asked the model to predict the recipient for a given call sample. We used a total of 437 calls from 99 individual callers to train the model.
Part of the reason we needed to use machine learning for this analysis is that rumbles convey multiple messages at once, including the identity, age and gender of the caller, emotional state and behavioral context. Names within these calls are likely to have only one minor component. A computer algorithm is often better than the human ear at detecting complex and subtle patterns.
We did not expect elephants to use names in all calls, but we had no way of knowing ahead of time which calls might have a name. Therefore, we included all rumbles when we thought they might use names at least some of the time in this analysis.
The model was able to identify the recipient for 27.5% of these calls – far better than a random guess would have achieved. This result indicated that some rumbles contained information that enabled the model to identify the intended recipient of the call.
But this result in itself was not enough evidence to conclude that there were names in the rumbles. For example, the model might have picked up the caller’s unique voice patterns and guessed who the recipient was based on how the caller usually addressed them.
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 really specific to individual recipients, like a name.
Next, we wanted to determine if elephants could detect and respond to their names. To find out, we played 17 elephants a recording of a call sent to them first and assumed it contained their name. Then, on another day, we played them a recording of the same caller sending someone else.
The elephants vocalized and approached the source of the sound more readily when the call was directed at them first. On average, they approached the speaker 128 seconds earlier, vocalized 87 seconds earlier and showed 2.3 times more vocalization in response to an intended call. That result told us that elephants can determine if a call was meant for them just by hearing the call out of context.
Unrecited names
Elephants are not the only animals with similar names. Bottlenose dolphins and some parrots address others by mimicking the addresser’s signature call, which is a unique “call sign” that dolphins and parrots commonly use to announce their own identity.
This system of naming by imitation is slightly different from the way names and other words normally 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 fundamental acoustic connection to what they refer to.
Arbitrary words are part of what allows us to talk about such a wide range of topics, including things and ideas that don’t make any sound.
Interestingly, we found that elephant calls sent to a particular recipient were no more similar to the recipient’s calls than to the calls of other individuals. This finding suggested that elephants could fight together without imitating the calls of the host, like humans, but unlike other animals.
What lies ahead
We’re still not sure where the elephants’ names are located within a call or how to tease them out from all the other information given during a rumble.
Next, we want to figure out how to isolate the names for specific individuals. Achieving this will allow us to address 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 do they ever talk about other people in their absence.
Name-like calls in elephants may tell researchers something about how human language evolved.
Most mammals, including our closest primate relatives, produce only a fixed set of utterances that are essentially pre-programmed into their brains at birth. But language depends on being able to learn new words.
Therefore, before our ancestors could develop a fully fledged language, they needed to develop the ability to learn new sounds. Dolphins, parrots and elephants have evolved this ability independently, and they all use it to address each other by name.
Our ancestors may have first evolved the ability to learn new sounds to learn each other’s names, and then later co-opted this ability to learn a wider range of words.
Our findings also highlight how complex elephants are. When arbitrary sounds are used to name other people, the ability to think abstractly is involved, as it uses sound as a symbol to represent another elephant.
The fact that elephants have to name each other in the first place shows the importance of their particular social bonds.
Learning about the elephant’s mind and its similarities to our own could increase human respect for elephants at a time when conflict with humans is one of the biggest threats to wild elephant survival.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. Written by Mickey Pardo, Colorado State University
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Mickey Pardo has received funding from the US National Science Foundation.
