Unlocking the Secrets of Bonobo Communication: Discover Their Surprising Connection to Human Speech

Humans have a unique talent for discussing a wide range of topics, thanks to a concept called compositionality. This is our ability to combine words in many ways, creating sentences with new meanings. For a long time, it was thought that only humans had this skill. Scientists believed animal communication was simpler, lacking the depth found in human language.

But a recent study changes that perception. We researched bonobos in the Kokolopori Community Reserve in the Democratic Republic of the Congo, discovering that they use compositionality in their vocal communications, much like humans do. This makes bonobos, our closest relatives, more intriguing.

Understanding Bonobo Communication

To study bonobos, we first needed to decode their calls. We learned that these calls can serve several purposes. A bonobo might give an order, express feelings, or signal an event, like a predator nearby.

We meticulously documented the context in which each call was used, tracking more than 300 factors. This included what was happening around the callers and how they acted after making a call. For instance, if a bonobo calls and then starts moving, that call likely means "I’m going."

Through this method, we created an extensive list of bonobo calls and their meanings, akin to a bonobo dictionary. This dictionary is groundbreaking because it’s the first comprehensive attempt to understand all calls from an animal species.

Call Combinations and Their Meanings

In examining combinations of calls, we found that some had meanings connected to their individual parts. This is a clear sign of compositionality. For example, if a bonobo makes two calls together, the new meaning often ties back to the meanings of the single calls—a trait we similarly see in human language.

Research in the past has shown that some animals can create simple or trivial compositions. For example, birds and primates can use combinations to convey basic ideas. However, our study identified more complex structures in bonobos’ calls, which were previously thought to be exclusive to humans.

To classify these combinations, we borrowed principles from linguistics. We determined that a combination only qualifies as compositional if:

1. Each part has a distinct meaning.
2. The combined meaning is different from the meanings of the individual parts.
3. The overall meaning derives from its parts.

This analysis allowed us to measure and understand the relationships between single calls and combinations, identifying several that meet these criteria.

Bonobo Communication and Human Language

Interestingly, our findings suggest that bonobos use a form of communication that includes complex layers, similar to human language structures. There were four key call combinations that clearly showed how meanings interact—something previously belittled as a human trait.

This research gives us insight into how language might have evolved. If bonobos are using compositionality now, then our common ancestor likely did too, dating back at least 7 million years. This striking similarity indicates the roots of language are deeper and older than many believed.

Final Thoughts

Understanding bonobo communication helps us appreciate the sophistication of animal interactions. It opens up new conversations about how language may have evolved across species. Bonobos aren’t just our closest relatives—they share aspects of communication that might reflect shared ancestry with us. The study brings us closer to understanding the origins of not just animal language, but our human language too.

For more on the fascinating world of animal communication, check out this report from Science on the topic.

Author: Mélissa Berthet, a biologist specializing in animal behavior at the University of Zurich.

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