An upside-down jellyfish drifts in a shallow lagoon, rhythmically contracting its translucent bell. By night that beat drops from roughly 36 pulses a minute to nearer 30, and the animal slips into a ...

Most animals don’t keep the same schedule we do. While we try to squeeze in eight hours and call it a good night, many animals snooze through more than half the day—and some barely stay awake at all.

Researchers developed a tiny, lightweight microscope that captures the electrical spikes of neurons at hundreds of frames per second in awake animals. WASHINGTON — Researchers have built a tiny, ...