A cave-dwelling Mexican tetra VPC Animals Photo / Alamy
Sleep is thought to be vital for the health of animals including us, but one kind of cavefish can somehow manage without it. Yet the cavefish appear to be healthy despite this lack of sleep, with normal lifespans.
Alex Keene at Texas A&M University first observed more than a decade ago that some fish from cave-dwelling populations of the Mexican tetra (Astyanax mexicanus) seem to barely sleep. “Some sleep a little bit,” says Keene. “A lot of the fish sleep zero hours.”
