Many frogs glow in blue light, and it may be a secret, eerie language

Twilight conditions may let the frogs' skin emit colors that can be easily seen by other frogs

A photo of a small green Sarayacu tree frog sitting on a green background.

The Sarayacu treefrog (Dendropsophus parviceps) is one of 151 frog species recently determined to fluoresce under the blue hues of twilight.

Santiago Ron

In the dim twilight hours, many frogs may be capable of emitting a faint green or orange glow.

A survey of hundreds of frogs in South America shows that far more frogs are biofluorescent than previously thought, researchers report in a preprint posted July 28 at