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MADRID.- The elephants They don’t just trumpet. That sharp sound, like that of a trumpet, could be compared to the human cry launched to alert or warn. But pachyderms also emit a range of low frequency harmonic sounds, like murmurs, which are specific to each animal. Now, assisted by an artificial intelligence system, a group of researchers demonstrates that they use specific sounds to call each member of the pack, as if they were calling them by name. Only humans did something like this until now.
Since 1986, scientists from Colorado State University (United States), two foundations and the Amboseli Elephant Research Project (Kenya) have been recording several herds of savannah elephants from three national parks or reserves. Over the years they have accumulated thousands of hours of recordings for the Elephants Voices project. With them they have been able to differentiate between various sounds. For example, a mother’s call to her daughter does not occur while she is in sight or is less than 50 meters away. They are contact calls. These murmurs also occur as a kind of greeting, when two members of the same pack meet, which cease when they touch each other. A third call is the one mothers use to comfort, nurse, or wake their young.
But Michael Pardo, a U.S. National Science Foundation graduate student at the University of Colorado, was convinced that more could be squeezed out of the noise collection. As his and Pardo’s research colleagues detail in the scientific journal Nature Ecology & Evolutiondesigned a machine learning system that could compare, analyze and decompose into its basic acoustic properties the calls made by 101 African elephants.
This artificial intelligence (AI) was able to identify the receiver in 27.5% of the calls issued by the pachyderms. A successful identification in just a third of the cases may not seem like much, but Pardo maintains the opposite: “It is not surprising that the model was only able to identify the receiver in 27.5% of the calls, because we would not expect the elephants They will use names on every call they make.” The researcher gives the example of humans and bottlenose dolphins, which also have a system for calling each other and “only use names in a small percentage of their expressions, so the same probably happens with elephants.” Since when starting the model, they did not know in advance which calls contained a name, they had to use all the calls they issued. “Therefore, it is not surprising that the model only correctly identified the receiver in a fraction of the calls,” he completes.
To confirm what was detected by the AI, they carried out a series of field experiments. In them, they reproduced several of the calls in the vicinity of their supposed recipients and, as a control group, near other elephants. Unequivocally, the animals to which a vocalization was not directed continued doing their thing. But in almost all cases in which the listener was the recipient identified by the system, he paid attention, raised his head and, almost always, answered the call and ended up heading towards the speaker.
The AI also wanted to answer one last question, which would be definitive to know if the elephants call the other members of the herd by name. The system grouped all calls made by different animals but with the same recipient. Without being identical (nor is how we each say “Peter!” or “Mary!”), they did observe that the different vocalizations with the same receiver had acoustic properties more similar to each other than to the others.
Pardo recognizes that they cannot be conclusive here. “On the one hand, calls from different individuals calling to the same receiver were more similar on average than calls from different animals calling to different receivers, suggesting that they call using the same (or at least similar) name,” he explains. Brown. “But, on the other hand, when we tried to train the machine learning model to identify patterns in calls that were for individual recipients regardless of who was calling (i.e., identify a common name that multiple recipients used to address the same recipient), it didn’t work. he could do it,” he adds.
The common or proper name is key. By definition, naming something is an innate skill, which has to be learned. Many social species already have it. Several arboreal primates emit different alarm sounds if the predator they have detected is coming from the sky, in the case of an eagle, or climbing up the tree, if it is a leopard. But naming in a specific, concrete way goes further. Very few animals, it has been proven in bottlenose dolphins and in several species of parrots and parakeets, use a specific vocalization and no other when they want to attract the attention of another member of the group. But what they do is imitate how she speaks and that’s how they manage to capture her.
Bruno Díaz is the scientific director of the Bottlenose Dolphin Research Institute (BDRI). He knows less about communication between elephants, but much about that between cetaceans. “Bottlenose dolphins have what we call whistle signature. The characteristics of the whistle include information about each individual, as if from a signature it was about” he says. “In some cases, especially in pairs with strong social ties, mothers and calves or pairs of males, it has been observed that one specimen can copy the signature whistle of the other as a sign of the strong bond between them,” she details.
But elephants do not imitate the vocalizations of the recipient of their call, “They do not rely on imitation to address another, something that resembles the way human names work,” highlights Pardo. Names, like almost all elements of human language, except onomatopoeia and little else, are arbitrary. In the succession of letters there is nothing that relates them to what is named. That gives great freedom to name everything new, but requires cognitive skills. This is explained by the scientific advisor of the organization Save the Elephants, director of Pardo’s work and senior author of the study, George Wittemyer: “I think that the arbitrary nature of the calls gives us an idea of their cognitive abilities. The ability to connect an arbitrary sound to an individual and for other members of a group to apparently recognize that arbitrary label suggests the ability to abstract thought, possibly symbolically”, but, he ends “I don’t think our study has proven it.” The next thing they are already working on is identifying the rest of the vocalizations, looking for a meaning or intention.
For Antonio J. Osuna, a researcher in animal cognition at the University of Veterinary Medicine in Vienna (Austria) not related to the research, “it is fascinating.” Speaking to SMC Spain, he adds that very little is known about communication in other species and “this is due (among other reasons) to the fact that we are not sensitive to the multiple subtleties that the vocalizations of other species may contain. They simply escape our capabilities. Thats why he machine learning “It is turning out to be so important: it allows us to highlight differences and similarities that, otherwise, we would never be able to distinguish.”
By Miguel Ángel Criado
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