Biofluorescence Discovered in Fire Salamanders

Researchers have discovered biofluorescence in fire salamanders (Salamandra salamandra) for the first time, revealing that exposure to ultraviolet light causes their skin and defensive secretions to emit a striking cyan-green glow that can persist for over 24 hours. Led by a team from the Max Planck Institute for Chemical Ecology and the Museum of Natural Sciences in Barcelona, the study published in Royal Society Open Science highlights that this phenomenon originates primarily from skin glands on the yellow underside and body sides, pointing to a close connection with chemical defense mechanisms. The authors emphasize that even well-studied species can harbor hidden traits, demonstrating how new observational tools uncover biological secrets that remain invisible to human eyes under normal daylight. While bioluminescence generates light independently through chemical reactions, the fire salamander's biofluorescence absorbs invisible ultraviolet wavelengths and re-emits them as visible cyan-green light, requiring an external light source like moonlight or starlight in dim forest habitats. The exact function of this cyan-green glow remains under investigation, with scientists hypothesizing potential roles in intraspecific communication, mate recognition, and reinforcing aposematic warning signals against predators. Because the fluorescence emanates from toxic skin secretions containing samandarines, it could actively influence predator interactions under nocturnal or low-light environmental conditions where ultraviolet and violet wavelengths are prevalent. The research team is currently working to isolate and chemically characterize the specific unknown molecules responsible for the fluorescence, which will clarify its evolutionary origins and ecological functions. Given that the International Union for Conservation of Nature lists fire salamanders as vulnerable due to habitat fragmentation and degradation, understanding every aspect of their biology is critical for their conservation.