There are currently no officially confirmed spiders that glow in the dark, although there have been numerous anecdotal reports of glowing spiders in the past, and some spiders have reflective pigments on their bodies which can make it seem like they are glowing.
One of the most notable reports of spiders that glow in the dark was by Barnum Brown in 1926, who claimed that there was a glowing spider in Burma. He claimed that the spider started glowing when it was in danger and that it had six or eight spots on its abdomen that made it glow.
However, there have not been any confirmed spider species that glow in the dark naturally. Some people might see spiders glowing because of their legs or eyes, but it’s unlikely that they have a glowing body.
Are there Spiders that Glow in the Dark?
There are currently no confirmed spider species that naturally glow in the dark, but there are some spiders that have patterns of pigmentation that make them appear as though they are shining in the dark.
Some spiders will glow when they are exposed to UV light, and it’s likely that the webs of spiders will also glow when they are exposed to the same type of light. This is more visible with UV light than white light, so you might not be able to see this feature of spiders all of the time.
However, sometimes, it might even be visible in normal light. This happens if the spider is exposed to ultraviolet light, and the spider will appear as though it is glowing because the UV light will bounce back from the body of the spider. However, this does not mean that the spider is glowing by itself.
Currently, there are no confirmed spiders that glow, but some people believe they have seen such a spider. At the moment, all of the evidence for glowing spiders is purely anecdotal.
Historical Reports of Glowing Spiders
The most significant report of glowing spiders comes from 1925 when paleontologist Barnum Brown spotted a glowing spider species while traveling in Burma. His findings were published in the scientific journal Nature in 1925.
In the report, Brown claims that he has seen a glowing, phosphorescent spider in Burma – more precisely, in Shillong. That is where he spotted a glowing spider that became glowing when it felt endangered. Brown argued that the spider started glowing from six or eight parts of its abdomen, as the lights switched on when it got frightened.
He saw the same spider species in Burma for a second time, this time a hundred miles away from the original sighting described above. In this case, he also saw a spider that was glowing when it felt in danger.
While it is possible that glowing spiders exist, it has not been confirmed officially, and all reported sightings haven’t been corroborated. One possible theory for historic glowing spider sightings is that a spider may have been infected or covered in bio-luminescent microorganisms or bacteria.
These reports tell us that while it is possible that glowing spiders exist, it is not very likely at the moment. Most animals that glow have discrete light organs, so they are not very visible at first sight.
Do Spiders Glow Under UV Light?
Some spiders glow or shine under UV light. This happens because of a chemical reaction in the body of the spider (or the web) which absorbs the UV light and reflects it back at the viewer as visible light.
Many arthropods including spiders and scorpions are known to glow under UV light. It’s also possible that the webs of spiders will also shine when they are exposed to UV light.
This happens because of a chemical reaction when the body of the spider (or the web) absorbs the UV light and starts emitting it away. So when the spider is exposed to UV light, it will start emitting that UV light backward again thanks to this chemical reaction. It’s an interesting phenomenon that not many people are aware of.
This feature is mostly visible with scorpions, which are the most notable animals that glow under UV light. Their exoskeletons will create a chemical reaction when they are exposed to such light. The exoskeleton will thus start absorbing this light and once enough of it is gathered, it will start glowing.
The same will happen with spiders and their exoskeleton. However, this feature is not seen with all spiders. In addition, it will also be seen with the webs of most spiders, because they have the same feature that scorpions do. The webs are covered with materials that absorb the UV light, which will cause the light to start glowing back.
Are there Spiders that Light Up?
No, there are no spiders that light up, but some species of spider have a special reflective layer behind their eyes which can give the appearance of glowing eyes.
This special layer is called tapetum lucidum, and enables spiders to see better in low-light conditions by bouncing light that enters their eyes back through their retinas a second time, similar to how night vision goggles work.
Spiders need to be able to see in low light to hunt their prey, which is usually small insects and occasionally other spiders.
Many other animals also share this feature including bats and cows, and it can give their eyes the appearance of producing light.
Wolf spiders, in particular, are knowing for having an intense glow from their eyes. They have very good eyesight – one of the best among spiders. which is useful for nocturnal hunting. And this causes their eyes to absorb the light and emit it back in the dark, which will make it seem as though these spiders are glowing in the dark.
At the moment, there are no confirmed species that would glow entirely in the dark, except for a few unsubstantiated instances where people have reported spiders to be naturally glowing.
However, not a lot of research has been done into this matter so it is not very clear yet whether there are some spiders that glow in the dark or not. It is clear that spiders glow because of UV light, but not many of them will glow because they will start glowing naturally.
There have been many reports of spiders glowing in the past, but officially, no spider species are described as glowing spiders.
While wolf spiders and other spiders with good eyesight might have their eyes glowing in the dark, this is also more of an illusion rather than these spiders really growing. At the moment, there has not been a lot of research done into this topic and it is not yet completely clear if any such species truly exist.
Stuart is the editor of Fauna Facts. He edits our writers’ work as well as contributing his own content. Stuart is passionate about sustainable farming and animal welfare and has written extensively on cows and geese for the site.