Birds, on the other hand, with fixed eyes, must turn their heads. Now, combine the fixed-eye situation with the final quirky fact: Most bird eyes sit on the sides of their heads--as robin eyes do.

The Great Potoo, a mysterious nocturnal bird from Central and South America has a unique ability - it can see even with its eyes closed. Image: X/@ElektraMadrigan.

Three elderly king penguins have been fitted with custom-made eye lenses during surgery to remove cataracts in what is believed to be a world first procedure to improve their sight, according to a ...