Blind cave fish have regional accents

In the underground caves of north-eastern Mexico, groups of blind fish that communicate using clicks seem to be developing cave-specific accents. Researchers studying the Mexican tetra (Astyanax mexicanus) analysed hours of fish chatter in six caves spread across the three mountain ranges. They noticed significant differences: clicks were relatively high-pitched in one cave, and deep and booming in another, for example. The linguistic split could eventually contribute to ongoing speciation among the fish.