Remora

ocean · clever adaptation · symbiosis

Suction-cup superstars. Remoras have an amazing disk on top of their heads that works like a vacuum cleaner. The disk has tiny slats that open and close to create powerful suction, letting them stick firmly to sharks, rays, whales, and even boats without hurting anyone.

Freeloaders with benefits. By attaching to larger animals, remoras get free transportation across the ocean without using much energy. They also snack on leftover food from their host's meals, making it a pretty sweet deal for the remora.

Quick getaway artists. Remoras can release their suction grip whenever they want by simply swimming forward. They're also excellent swimmers on their own, moving with smooth, curved motions through the water like underwater snakes.

Size varies wildly. Different remora species grow anywhere from 30 centimeters (about one foot) to 110 centimeters (over three feet) long, so some are tiny while others are pretty hefty.