A group at Keio University has clarified that different physical reactions occur in crows depending on the relationship (superiority or inferiority) with the person they are facing.

 It is known that communication with a partner with whom one has a tense or friendly relationship involves not only brain activity but also body reactions such as changes in heart rate, and the brain and body work interactively.This is thought to work not only in humans but also in various social animals, but so far there have been no studies examining how the body works in communication situations in birds.

 It is known that crows run complex societies, such as distinguishing between each other individually and constructing tense relationships based on superiority (strong or weak) and friendly relationships in which they exchange grooming. .In this study, we focused on large-billed crows inhabiting Japan, and investigated how their heart rate and autonomic nervous system changed during communication with a partner who has such a specific relationship.

 During the experiment, by attaching a wireless electrocardiograph to the chest of the tall glass, along with a special vest to prevent it from falling off, we established the world's first system for recording electrocardiograms from freely moving crows.Using this, electrocardiograms were recorded in two large-breasted crows in a superior-inferior relationship in a laboratory, and heart rate and activity balance of the autonomic nerves (sympathetic and parasympathetic nerves) were analyzed.

 As a result, the heart rate of the inferior male who faced the dominant male decreased compared to before the meeting, and the activation of the parasympathetic nerve occurred.On the other hand, there was no change in the heart rate of the mating dominant male, and the sympathetic nervous system was activated.In humans and rodents, it has been suggested that hypocardiacs associated with parasympathetic activity are associated with negative emotions such as disgust and fear.In this study, it is possible that the physical reactions of inferior male crows may also be based on negative emotions such as ``disgust'' and ``scary'' toward superior males.

 This study showed that birds also evolved a mechanism for generating physical reactions according to their relationship with each other, and it can be said that important suggestions were given to elucidate the evolution of the mind in various animals in the future.

Paper information:[Royal Society Open Science] Social encounters produce different autonomic responses between dominants and subordinates in crows

Keio University

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