Two species of small, deep-dwelling fish called pearlsides possess eye cells that break the rules of vertebrate vision, combining features of rods and cones into a single hybrid photoreceptor never ...

Schools of fish are mesmerizing examples of collective animal behavior. Thousands of individuals move in near-perfect synchrony, despite each fish having only a limited view of their surroundings. How ...

Humans and other mammals cycle through distinct sleep phases. One of them is easily recognized by the darting motion of the ...