2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
German scientists have discovered separate sounds in the communication system of green monkeys (Chlorocebus sabaeus), with the help of which they inform their relatives that they have seen a drone. The sounds recorded by the scientists were not similar to those used by this species, but in spatial and temporal characteristics they were similar to the calls of the vervet (Chlorocebus pygerythrus) at the sight of danger in the air. Article published in Nature Ecology & Evolution.
The communication system of social animals is quite diverse: depending on the species and habitat, their vocabulary may contain sounds that signal the location of food, the presence of danger, or simply their own position. At the same time, it is not clear whether the language of animals is capable of developing as quickly as human: in other words, it is not known how quickly the necessary cries appear in their vocabulary under the influence of a changing environment.
Scientists from the German Center for Primatology under the leadership of Julia Fischer decided to check the evolution of the communication system of green monkeys in their natural habitat. They studied the population of monkeys in one of the Senegalese national parks. The researchers report that monkeys living in the area under study never made disturbing sounds when they saw objects in flight (such as birds) - partly because they were seen very rarely, and partly because they probably did not consider what they saw as a threat.
During the experiment, a drone was launched with the participating monkeys: the monkeys began to scream and hide. After that, scientists turned on the sound of a drone taking off for the monkeys separately - and compared the spectrograms and their screams in response to the sounds that the monkeys made when they heard a leopard or a snake.
The monkeys very quickly learned the new "word" and used it when the drone sounded after the first meeting. Interestingly, in terms of spatial and temporal characteristics, the sound was very different from the one that monkeys made in response to known threats - a leopard or a snake. Scientists further compared the received sounds with the cries of vervettes - they were already familiar with the threat from the air and have a communication system similar to green monkeys. It turned out that the cry of green monkeys at the sight of a drone is very similar to the sounds that vervettes make when a flying predator approaches.
Comparison of sounds of a) female green monkeys b) female vervettes c) male green monkeys and d) male vervettes
The authors of the work came to the conclusion that, despite the fact that the green monkeys borrowed the "word" from a closely related species (that is, in fact, it was not new), its introduction into their vocabulary took place rather quickly. This may indicate that the communication system of monkeys, like the human language, is a system that develops and adapts to changes in the environment.
Studying the communication system of primates is a rather important task, especially from the point of view of the evolution of human communication. Scientists recently found that babies under the age of two use the same gestures as great apes.