Glowing Geckos

Glow-in-the-dark clothes are awesome. Even lizards know it! The web-footed gecko, found in the desert in Namibia, has glow-in-the-dark skin. They have skin cells called iridophores, that are filled with guanine crystals. Many reptiles also glow under ultra-violet light, and even have fluorescent bones! It helps them see each other over long distances.