Watch These Millipedes Glow in the Dark

The millipede Motyxia sequoiae, which lives at the upper elevations of the Sierra Nevada, glows bluish green—a warning to predators that the arthropod contains toxic cyanide. All 11 species and subspecies in the genus Motyxia glow, but those at lower elevations of the mountains glow less brightly. Scientists now think the bioluminescence first evolved as a way for millipedes at lower elevations to cope with the stress of living in a hot, dry environment and later evolved into a warning signal as the species