About 20,000 years ago, a species of fish began populating small pools in dark caves in Mexico – and the fish in each cave use clicks to communicate in distinct ways.
among the cave-dwellers as they adjusted to living in darkness. A particular form of sharp click used by sighted fish in aggressive encounters, for example, is produced by their blind counterparts while foraging.at Harvard University wondered if the communication also varied between fish evolving in different caves.
Sounds in a cave called Los Sabinos were similar to nearby Chica, but also Subterráneo and Molino, which are in different regions. This supports the idea that the sounds evolved independently and weren’t related to physical proximity. The new accents are probably the result of totally random genetic drift, says Sylvie Rétaux at the University of Paris-Saclay, a co-author of the study.