Q: I recently moved to Arizona and hear that scorpions glow in the dark. Is
true? If it is true, why do they? Clem E., Thatcher, Arizona
[Chain Reaction, Arizona State University] Scorpions glow
blue-green or yellow-green in the dark
A: Yes. All scorpions glow in the darkóeven after death, even fossilized!
A thin, transparent film (hyaline) in the outermost layer (cuticle) of their
exoskeleton contains a protein that fluoresces. At night in the Arizona desert,
you can see scorpions within a 20-foot radius by shining a black (ultraviolet)
light around. They glow bright green-blue or green-yellow like scorpion jewels.
Newly molted scorpions donít fluoresce. As the cuticle hardens, it glows
more. The hylane skin toughens into an incredible substance. After hundreds of
millions of years, after all other cuticle layers are lost, the hyaline layer
remains, fossilized in rocks. It still glows.
We donít know why scorpions fluoresce. Maybe it helps the antisocial
creatures locate each other in the dark and either stay away (usually) or find a
mate. Scorpions hunt at night and gladly eat fellow scorpions. In fact, mating
is an extremely dangerous activity (to the smaller, usually male, partner).
Arizona State University, Chain Reaction: Fangs and stingers
Scott Stockwellís Scorpion Emporium:
Scorpion fluorescence and getting a black light
Journey to wild places: scorpions
Arizona State University, Chain reaction: solar system, desert,
and weather facts
(Answered June 27, 2003)