In 2016, Nobuaki Mizumoto, a biologist from Arizona State University, happened to encounter this bizarre fossil dated approximately 50 million years ago. This fossil seemed to show a group of fish heading to the same direction, possibly migrating. Does this suggest that fish have been traveling in groups far longer than scientists realized? The answer is most likely yes.
As Lucas Joel reports for The New York Times, the 259 juvenile fish found in the fossil likely belong to the extinct species Erismatopterus levatus. All of the specimens are facing the same direction, and each measures under an inch long. Much like modern schools of fish, the prehistoric one seems to adhere to the laws of attraction and repulsion, with members maintaining enough distance between neighbors without straying too far from the group.
To better gauge the school’s movements in life, the team measured the exact position and direction of each individual fish. Next, Gizmodo’s George Dvorsky writes, the scientists ran 1,000 computer simulations designed to predict the group’s most plausible next position, as determined by factors including water currents and spatial distribution. Overall, the models appear to align with behaviors exhibited by modern fish schools, or shoals, suggesting that the fish in question were, as NOVA Next’s Katherine J. Wu writes, “undulating along in a coordinated fashion,” when they met their demise.
(Image Credit: Mizumoto et al.)