SPECIES: Fratercula arctica
I HAVE BUILT-IN DIVING GOGGLES
Fifty, 100, 200 feet— Fratercula arctica dives deeper and deeper into the sea, all the while repeatedly snapping its beak with unerring precision. Its prey do not stand a chance— even though this lightning-fast hunter isn’t really in its own element. That occurs far above the water. But how does this animal manage to orient itself so perfectly in this alien environment? Researchers have discovered: It’s a unique visual system that has made Fratercula arctica one of evolution’s success stories. Not only does each eye have an upper and lower eyelid, there is an additional third eyelid known as a nictitating membrane. During the hunt for herring and smelt, the third eyelids work like a pair of goggles to cover the corneas while the animal is in the water and allow it to see clearly for dozens of yards— and capture its fill of prey.