Sightlessness is a common adaptation of cave-dwelling animals. Sometimes, as in the case of the Olm eyeless cave salamander or “human fish,” they no longer even have eyes. Now scientists have learned that at least in a certain kind of cavefish, the Mexican blind cavefish, sleep, too, is a waste of resources.
Well, that’s not quite the right way to put it. It’s not so much that the fish don’t need sleep, it’s that they need to stay awake more, said the researchers in a press release.
“These fish live in an environment where food is generally scarce,” said Richard Borowsky of New York University. “If you are asleep when a bit of food floats by, you are out of a meal and out of luck.”
Borowsky and lead author of the study Erik Duboué first observed hints of the insomniac tendency of cavefish in the laboratory. Fish that typically hang out in brighter surface waters showed obvious sleep patterns. At night, they would get droopy fins and sink to the bottom of their tank. Captive cavefish on the other hand kept patrolling around the clock.
Cross breeding cavefish with other fish has shown that the wakefulness is genetic. Besides the gee whiz factor of the find, scientists think that this cave critter could hold clues to understanding sleep disorder in humans. That’s because the same gene that keeps the fish partying all night long, is likely also the gene that regulates similar behavior in other animals.
Current Biology, April 7 issue
Authors and Affiliations:
Richard Borowsky of New York University
Erik Duboué of New York University
Elisabeth Lyons, firstname.lastname@example.org, 617-386-2121