Hyacinthe, C., Attia, J. Rétaux, S. Nat. Commun. 10, 4231 (2019)

Though they are still the same species, the cave- and river-adapted populations of the Mexican tetra, Astyanax mexicanus differ in a number of notable morphological, physiological, and behavioral ways. A new study from researchers working in the lab in France as well as in the field in Mexico adds the tetras; communication styles to the list.

The fish are indeed prolific acoustic communicators in the lab and in the wild. They make the same six types of sounds—simple clocs, clicks, and sharp clicks as well as more complex serial clocs, serial clicks, and rumblings—but the morphs vary in how they use those sounds under different social contexts. The cave-dwellers, which have lost their eyesight in their years living without light, seem to chatter to keep tabs on other each in the dark.