A research group led by Dr. Munehiko Ito (at the time of research) of the Graduate University for Advanced Studies has shown for the first time in the world that a fish called Julidochromis legani (hereinafter abbreviated as legani) behaves in eights.
Socially complex behaviors such as eight hits have been thought to be found only in animals with sophisticated cognitive abilities.So far, the eight-hit behavior has been scientifically proven only in humans, non-human primates, and other social carnivores.
This time, the group placed three leganis of different lengths in a large aquarium and carefully recorded who attacked whom.Attacks basically occur from large to small individuals.Three individuals were designated as L, M, and S in descending order of body length, and when the time series of attack behavior was analyzed, after the L individual attacked the M individual, the M individual attacked the S individual within 5 seconds. "Behavior" was seen frequently.
Based on this new finding, the group further examined behavior and proposed two effects of behavior per eight.One is the effect of "changing the point of attack to an S individual" by hitting eight S individuals with an M individual attacked by an L individual.The other is the effect of "maintaining one's position" by having the M individual attacked by the L individual attack the S individual immediately after hitting eight.
Traditionally, fish have been thought to be organisms with only simple cognitive and behavioral patterns, but this result overturns this, and that fish also perform advanced social information processing and decision-making. Indicated.
