In eastern Mexico’s underground caverns and streams, a blind fish undergoes a peculiar adolescence: as it approaches maturity, taste buds begin to sprout under its chin and on top of its head, creeping toward its back.
“It’s a pretty wild amplification of the sensory system of taste,” says Josh Gross, an evolutionary geneticist at the University of Cincinnati and a co-author of a recent study on the cave fish in Nature Communications Biology. Gross and his team discovered that the new buds blossom around the time when the fish transition from eating larval crustaceans to gobbling up their adulthood staple: bat guano. Taste buds outside their mouths might be helping the fish detect bat droppings in the utterly dark, “food-starved” caves, Gross says. {read}