Sight and light are always associated in our minds. Sunlight illuminates the Earth every day, allowing plants and animals to thrive. But how do living things without eyes ensure they get enough exposure to light when they can't see it? Research has shown that many species of eyeless animals can still detect light and respond to it. Even without sight, they have evolved to perceive elements of the natural world by other means. Some animals with highly sophisticated eyes also use other parts of their bodies to see.
Click through the following gallery to see which fascinating creatures see the world without eyes, and how they do it.