תפריט כתבה
What an ancient jellyfish can teach us about the evolution of sleep
Phys
21:30
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 state that, despite its lack of a brain, resembles sleep.
