World's biggest spiderweb discovered inside 'Sulfur Cave' with 111,000 arachnids living in pitch black

Live Science ^ | 4 November 2025 | Sascha Pare

[fidelis]

A giant colonial spiderweb in a sulfuric cave on the border between Greece and Albania may be the largest ever found — and it was built by spiders we didn't know liked the company of others.

Researchers have discovered more than 111,000 spiders thriving in what appears to be the world's biggest spiderweb, deep inside a pitch-black cave on the Albanian-Greek border.

The "extraordinary" colony consists of a colossal web in a permanently dark zone of the cavern, according to a study published Oct. 17 in the journal Subterranean Biology. The web stretches 1,140 square feet (106 square meters) along the wall of a narrow, low-ceilinged passage near the entrance of the cave. It is a patchwork of thousands of individual, funnel-shaped webs, the researchers noted.

This is the first evidence of colonial behavior in two common spider species and likely represents the largest spiderweb in the world, said study lead author István Urák, an associate professor of biology at Sapientia Hungarian University of Transylvania in Romania.

The spider megacity is located in Sulfur Cave, a cavern that was hollowed out by sulfuric acid formed from the oxidation of hydrogen sulfide in groundwater. While the researchers revealed tantalizing new information about Sulfur Cave's spider colony, they weren't the first to see the giant web. Cavers with the Czech Speleological Society discovered it in 2022 during an expedition in the Vromoner Canyon. A team of scientists then visited the cave in 2024, plucking specimens from the web that Urák analyzed before going on his own expedition to Sulfur Cave.

[Tallguy]

The colony still must be trapping enough calories to support the colony, a significant percentage of it anyway. Otherwise it would be a biological perpetual motion machine. Can’t violate the laws of Thermodynamics.

[JimRed]

There must be a whole lot of other bugs in that dark cave, to feed 11,000 spiders!

[UnwashedPeasant]

"Who was the poor schlemiel whose job it was to COUNT them"

Me: 109,904... 109,905...
Coworker: Hey what time is it.
Me: It's 11:15. Oh shoot! 1... 2... 3...

[left that other site]

Bwahahahahahahahahaha!!

[fidelis]

You just gotta catch them one at a time.

[left that other site]

YIKES!

[wafflehouse]

“lets go into this permanently dark cave that has half a million spiders in it”

[matt04]

I feel like that would be a good spot to test a small nuclear weapon.

[fidelis]

Personally I think spiders are cool...

...unless they get near my person...

...Then I'm like:

[Attention Surplus Disorder]

Who counted the spiders?

[larrytown]

"Nope! Nope Nope Nope!"

This! This! This! This!

[Billthedrill]

Who counted the spiders?

Some fields, it just sucks to be a graduate student.

[HartleyMBaldwin]

That would be enough to make a guy quit spider research and take a job in a putty knife factory.

[fidelis]

Who counted the spiders?

Who else?

[Organic Panic]

I was just gonna ask “what do they eat?”

[willk]

“What is their food source????”

I’d like it to be George Soros.

[Salamander]

Cool!

[Salamander]

You could see swarms of fling insects in the video.

There’s food down there and spiders really don’t need frequent meals.

[Salamander]

I pick them up and move them out of harms way all the time.

[faucetman]

I can’t read this, I’ll never sleep again.