Why Do Scorpions Glow Under Ultraviolet Light?

Why do scorpions glow in uv light is a question asked by many people. Scorpions are fascinating creatures, known for their venomous stings and hardy survival skills. But one of their most intriguing characteristics is their ability to glow a vibrant blue-green under ultraviolet (UV) light.

This fascinating phenomenon has long intrigued scientists, and recent research has shed some light (pun intended) on the reasons behind this characteristic fluorescence.

What is Fluorescence?

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation.

The most striking example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the spectrum, and thus invisible to the human eye, while the emitted light is in the visible region.

Scorpions and Fluorescence

When exposed to UV or black light, scorpions emit a bright blue-green glow. This is due to the presence of fluorescent compounds in the exoskeleton, or cuticle, of the scorpion. These compounds absorb the UV light and re-emit it as visible light, causing the scorpion to glow.


One of the key components responsible for scorpion fluorescence is a group of compounds called beta-carbolines. These molecules are found in the exuviae (shed exoskeletons) of scorpions, such as in the case of the scorpion species Liocheles australasiae, according to a study.

The beta-carbolines present in their exoskeletons are believed to function as a protective layer, shielding them from DNA damage caused by solar UV radiation.

Beta-carbolines exhibit fluorescence due to their unique chemical structure, which consists of a fused five- and six-membered ring system containing two nitrogen atoms. Their electron properties allow them to absorb UV light and emit visible light, causing the distinctive glowing effect seen in scorpions.

While beta-carbolines are the primary components linked to scorpion fluorescence, future investigations should also assess the chemical composition of the exocuticular hyaline layer of other arthropods, such as sea scorpions and horseshoe crabs, to better understand the evolutionary role and origins of cuticular fluorescence in chelicerates as suggested by a study.

Theories Behind What Makes Scorpions Glow Under UV Light

While the mechanism of fluorescence in scorpions is understood, the reason why scorpions have evolved this trait remains a mystery.

Several theories have been proposed:

  1. Predator Avoidance: Some researchers suggest that the fluorescence could serve as a warning to predators. The glow could signal the scorpion’s venomous nature, discouraging potential threats.

  2. Mating Rituals: Another theory posits that the glow could play a role in scorpion mating rituals. However, this theory is less supported as scorpions are known to be largely solitary creatures.
  3. Research has suggested that scorpion fluorescence might play a role in their perception of light. In a study by Science Direct, scorpions with their eyes blocked were found to react differently under green light compared to UV light, indicating that fluorescence could influence their behaviour in response to different light sources.
  4. Light Detection: Perhaps the most compelling theory is that scorpions use their whole bodies as a light sensor. The fluorescence could help them determine whether to come to the surface or stay underground, depending on the amount of UV light present.

Ongoing Research

Despite these theories, the exact reason why scorpions fluoresce remains an active area of research. Scientists continue to study this unique trait, hoping to unlock more of the scorpion’s secrets. This research could lead to new insights into the evolution of these resilient arachnids and potentially inspire new technologies.

The fluorescence of scorpions under UV light is a captivating phenomenon that highlights the complexity and mystery of the natural world. As we continue to explore and understand these creatures, we are reminded of the endless wonders that nature has to offer.

Come And See Them

To witness this phenomenon first hand, why not take part in our guided scorpion walk, where you will have the opportunity to see the scorpions glow in the dark?