Researchers have uncovered what may be the largest spiderweb on Earth, and it’s the stuff of nightmares. More than 111,000 spiders are living together inside a pitch-black cave on the Albanian-Greek border, forming a colossal web stretching over 1,100 square feet.
This isn’t Shelob’s Lair from The Lord of the Rings. This is real. Luckily, there are no giant spiders to be found among the 111,000 arachnids.
The discovery, published October 17 in Subterranean Biology, reveals a sprawling network of interconnected funnel-shaped webs coating a low, narrow passage near the cave entrance. The cave, known as Sulfur Cave, sits in a permanently dark zone carved out by sulfuric acid over centuries.
Study lead author István Urák, a biology professor at Sapientia Hungarian University of Transylvania, told LiveScience the sight left him overwhelmed.
“If I were to attempt to put into words all the emotions that surged through me [when I saw the web], I would highlight admiration, respect, and gratitude. You have to experience it to truly know what it feels like,” he said.
Over 111,000 spiders found in pitch black cave with gigantic spiderweb
The massive colony marks the first documented case of colonial behavior in two spider species. Researchers estimate around 69,000 Tegenaria domestica spiders and more than 42,000 Prinerigone vagans are sharing the same sprawling structure.
“We report the discovery and detailed analysis of an extraordinary colonial spider assemblage in Sulfur Cave,” the study notes, adding that the cave’s unique sulfur-rich environment may have encouraged the species to cluster together in record-breaking numbers.
The web was first spotted in 2022 by cavers with the Czech Speleological Society, who tipped off researchers. Scientists later collected specimens in early 2024 before returning to fully document the site.
While arachnophobes would likely describe the cave as the last place on Earth they’d ever step foot in, scientists see it as a breakthrough in understanding spider behavior.
“The natural world still holds countless surprises for us,” Urák said.
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