Ducks Have Built-In Goggles to See Underwater
Ducks possess a transparent third eyelid called a nictitating membrane that sweeps across their eyes like a windshield wiper while they swim underwater. This clear eyelid lets them see clearly beneath the surface without any blurriness, allowing them to spot food and navigate safely.
💡 Fun detail:
The membrane is so efficient that some ducks can read underwater signs if humans placed them there—imagine swimming goggles that never fog up!
Source: National Geographic