Why do cave fish lose their eyes?
Sometimes, when we lead students or beginning cave explorers into their first “wild” cave, we turn out all our lights at our first rest stop. For many people, the experience of total darkness is stunning, and even a bit overwhelming. Wave a hand in front of your face, and you see nothing. Yet other senses seem to come alive. If the cave is wet, you can hear the drip, drip, drip of water across the chamber. You can smell the earth and damp air as the cave “breathes.” As you grope for the comforting switch on your electric headlamp–or the flint lighter of your carbide lamp–your spatial sense, or proprioception, becomes keen and alert. If you leave the lights off for a few minutes, you might even begin to “see” how, with patience, you could learn a lot about your surroundings–and perhaps move about (if there are no deep pits nearby!) without the sense of sight at all.
