The Mexican cavefish have no eyes, little pigment, and require about two hours of sleep per night to survive, reports Popular Science.


“We think we can use cavefish to ask fundamental questions about why we sleep and why there is so much variation in sleep across the animal kingdom,” says Alex Keene, lead author of the paper and a neuroscientist at Florida Atlantic University. “If we can figure out why these fish get by despite little sleep, we may be able to find better ways to manipulate sleep in humans.”