Studying communication in elephants is a discipline that is as fascinating as it is complicated. The conversations between pachyderms are rich and layered, a combination of trumpets, roars and rumbles at very low frequency, so low as to be inaudible to us humans.
It’s one of those cases where the machine learning becomes essential, for example to identify individual calls and attribute them to this or that individual. This is what a team of researchers from the non-profit Earth Species Project and ElephantVoices did, who used artificial intelligence to analyze elephant rumbles in particular, discovering that the pachyderms harmonize them during their conversations. The study is published on Scientific Reports.
The cocktail party problem
The main problem in interpreting conversations between elephants is the so-called “cocktail party effect”: when there are too many voices at the same time, our brain tends to focus on just one while ignoring the others. The same goes for elephants: we have thousands of recordings of their roars and trumpets, but it is not easy for our ears to associate each call with a specific specimen. In short, when elephants communicate there are too many sounds for the ears and brain to handle them.
Hence the use of machine learning: The team fed 902 different recordings of elephant roars into the computer, all captured in Amboseli National Park, Kenya. The calls were identified, associated with whoever issued them and also classified into six different social categories, depending on when they were launched: staying in contact during a separation, preparing to move, coordinating one’s movements, comforting puppies, greeting family members, participating in extended family reunions.
Harmony not just vocal
The analysis of the rhombuses revealed that, in many cases, the elephants harmonize these calls during the chat: as if, sentence after sentence, the animals all began to speak in the same way – exactly as happens to us humans when we “pick up” the way of speaking of the person we are conversing with, and perhaps even the accent. This harmonization is not just a quirk: it is used above all when groups of elephants separate but want to stay in touch, when they have to coordinate a move, and finally when they say goodbye after not seeing each other for a while.
These findings suggest that rumbles, which are very low-frequency calls that can travel long distances, are a way to coordinate and facilitate more complex social interactions.
In other words, when the elephants all start talking the same way it is because they have found an agreement and decided how to proceed. It’s not just a fascinating discovery: if we could better decode the rumbles, we could use them for conservation purposes, tracking and even anticipating the movements of elephant herds simply by listening to what they say.
