A scientist is studying a fish fossil from 50 million years ago to learn about the motion of ancient fish species. The limestone shale fossil reveals that the small extinct fish species, known as Erismatopterus levatus, likely swam as a shoal. This shows that coordinated motion could have been around millions of years ago during the Eocene Epoch.
Studying the Collective Motion of Ancient Fish
The recent study by Nobuaki Mizumoto, a behavioral ecologist at Arizona State University, is published in the Proceedings of the Royal Society B. The fossil shows a group of fish numbering 259 swimming in the same direction. It has been analyzed to understand the exact orientation of the school of fish and the reasons behind this. There is no clear indication what could have led to the death of these fish, but one of the suggestions put forward by researchers is that a sand dune could have collapsed and buried the mass of fish in an instant.
Fish swimming as a school today follow certain rules to allow them to coordinate their movement seamlessly. These rules are related to attraction and repulsion and govern the positions and movements of each of the fish as well as the direction that the entire shoal is moving.
It is known that many animal species that move in a group have special ways of coordinating themselves. Not much research has been done about this collective behavior as far as ancient and extinct animal species are concerned. It is also unknown when this kind of behavior evolved. These are some of the reasons why the research by Nobuaki Mizumoto is contributing to this growing body of knowledge. Mizumoto’s research was initially centered around how termites work together to build impressive structures. The scientist started looking into ancient fish collective behavior after finding the fossil in Katsuyama, Japan, in 2016.