Toshiki Suzuki, a researcher at the Center for Ecology Research, Kyoto University, has revealed for the first time in the world the ability to imagine the referent from words in animals other than humans.
When the wild bird great tit finds its natural enemy, the snake (rat snake), it makes a special cry that sounds like a "jar jar" and alerts its friends.This bark is only emitted when a snake is encountered.Traditionally, animal communication has been considered to be a "command" in which the speaker mechanically manipulates the behavior of the listener.This time, we experimentally verified whether or not the cry (think of it as a word) reminds a companion of the image of a snake, as in human language.
Great tit approaches and threatens when it encounters a snake.So, I played a snake-specific bark from the speaker to attract the great tit, attached a string to a tree branch cut to about 20 cm, pulled it from a distance, and moved the snake to climb up the trunk.As a result, almost all great tit (12 out of 11) approached the movement of the branches within 1 m.On the other hand, the other calls (collective voice, alert voice) did not approach the movement of the branches.
On the other hand, when the branches were made to move differently from the snake and a snake-specific voice was heard, they hardly approached.In other words, it was found that the great tit, which heard a snake-specific voice, did not simply approach a moving object, but approached a trunk or a branch on the ground like a snake.
As a result, it was found that the great tit recalls the visual image of a "snake" from the snake-specific bark, even if there is no snake in front of it, and applies it to the object in front of it to search for the snake.This is an epoch-making achievement showing that birds understand the meaning of speech using a cognitive mechanism similar to that of humans.
Paper information:[Proceedings of the National Academy of Sciences of the United States of America] Alarm calls evoke a visual search image of a predator in birds
