A School of Fossilized Fish
The results of recently analyzed find from the Green River Formation in the western US were published yesterday show the fossilized remains of an entire school of 257 fish. Beyond the fact that a whole school of fish was somehow frozen in time together 50 million years ago, what’s so remarkable is this discovery provides evidence of the social behavior of a now-extinct animal.
We found traces of two rules for social interaction similar to those used by extant fishes: repulsion from close individuals and attraction towards neighbours at a distance. Moreover, the fossilized fish showed group-level structures in the form of oblong shape and high polarization, both of which we successfully reproduced in simulations incorporating the inferred behavioural rules. Although it remains unclear how the fish shoal’s structure was preserved in the fossil, these findings suggest that fishes have been forming shoals by combining sets of simple behavioural rules since at least the Eocene. Our study highlights the possibility of exploring the social communication of extinct animals, which has been thought to leave no fossil record.
Read more about the analysis in Science News.
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