Somalian cave fish live on a 47-hour day
These fish are native to the limestone caverns found deep beneath the Somalian desert. As you might imagine, these are creatures of eternal darkness, and thus the terms “night” and “day” are meaningless. And that’s what makes their biological clocks so bizarre. The Somalian cave fish, or Phreatichthys andruzzii, has an internal biological clock just…
