Sharks Do Something Strange When Upside-Down, and Scientists Aren’t Sure Why

Flip certain sharks upside down, and they’ll suddenly go limp. Their bodies slacken, their fins stop moving, and for a moment, it’s like they’ve completely checked out. It looks like they’re faking death. But scientists still don’t know what they’re doing or why it happens. The reaction is called tonic immobility, and it’s not unique […]