Glowing Bones

Chameleons have some amazing features, like super-stretchy, sticky tongues and skin that can change color. Now, researchers have discovered something else remarkable about the lizards—some of them have bones that can glow in the dark.

To study this phenomenon, researchers shone invisible ultraviolet (UV) light onto chameleons belonging to 51 different species from Madagascar. Boney growths known as tubercles beneath the skin of 37 chameleon species absorbed the light and glowed blue in response. This ability to absorb and then emit light is called fluorescence.

Many animals, like fireflies and jellyfish, can glow. But most rely on phosphorescence—chemical reactions inside their bodies that produce light. Fluorescence is rarer.

David Prötzel, a researcher at Ludwig-Maximilians University in Germany, helped make the discovery. He thinks a chameleon’s ability to glow in the dark might be useful in identifying other members of the same species. “We already knew that chameleons communicate with color changes, so this trait makes perfect sense,” he says.