Blind Mexican cavefish sleep much less than closely related species that live near the surface, according to a study that involved shaking aquariums to keep fish awake.

By breeding the fish with their sighted counterparts, scientists determined that the difference in their sleep patterns is genetic. The discovery may help identify genes and pathways involved in insomnia and other sleep disorders in humans.

.Insomniac Cavefish May Hold Clues to Human Sleep Disorders | Wired Science | Wired.com.