If you apply for an ID card or unexpectedly end up at the police station, you must hand in your dermatoglyphic pattern. Dermatoglyphic pattern? Yes, your fingerprint: a pattern of arcs, loops, and twists on the tips of your fingers. Even for identical twins, fingerprints are unique. You’ll find that even animals have fingerprints. In fact, koala fingerprints are so similar to human fingerprints that they’re barely distinguishable from each other under a microscope. Your fingerprint is your identity. So you shouldn't just leave it lying around. Not in real life and not online.