Scientists discovered the world’s largest known spider web in Sulfur Cave on the Greece–Albania border, covering 1,076.4 sq ft and hosting an estimated 110,000 spiders. The colony includes approximately 69,000 Tegenaria domestica and 42,000 Prinerigone vagans, marking the first documented colonial web for these species. Genetic analyses show the cave populations are distinct, and researchers noted seasonal reproductive patterns for T. domestica. The cave also supports 512 other species across 20 families, underscoring its ecological richness.
Scientists Discover World's Largest Spider Web in Underwater Cave — Home to ~110,000 Spiders
Scientists discovered the world’s largest known spider web in Sulfur Cave on the Greece–Albania border, covering 1,076.4 sq ft and hosting an estimated 110,000 spiders. The colony includes approximately 69,000 Tegenaria domestica and 42,000 Prinerigone vagans, marking the first documented colonial web for these species. Genetic analyses show the cave populations are distinct, and researchers noted seasonal reproductive patterns for T. domestica. The cave also supports 512 other species across 20 families, underscoring its ecological richness.
03:38 PM, 11/11/2025Science
Largest known spider web found in underwater Sulfur Cave on the Greece–Albania border
Researchers have identified what appears to be the world’s largest spider web inside an underwater grotto known as Sulfur Cave, which straddles the border between Greece and Albania. The web covers a surface area of 1,076.4 square feet along the cave wall and supports an estimated colony of about 110,000 spiders, according to a study published in the journal Subterranean Biology.
Field counts estimated roughly 69,000 individuals of Tegenaria domestica and about 42,000 of Prinerigone vagans living on the same continuous web. The authors note this is the first documented case of colonial web formation for these two species, which are not typically considered social.
Genetic analyses confirmed the species identities and showed that the Sulfur Cave populations are genetically distinct from other known populations. For Tegenaria domestica, researchers also observed a seasonal reproductive pattern, with significantly larger egg clutches recorded in early summer.
The study attributes the colony’s size and persistence to abundant resources within the cave ecosystem. In addition to the spider colony, scientists recorded 512 other species representing 20 different families, highlighting the cave’s rich subterranean biodiversity.
The web was first reported by a team from the Czech Speleological Society during a 2022 expedition. Researcher István Urák of Sapientia Hungarian University of Transylvania examined and documented the structure in 2024.
“It is a unique case of two species cohabiting within the same web structure in this huge number: approximately 69,000 Tegenaria domestica coexist with about 42,000 Prinerigone vagans on this single large web,” Urák said. “Admiration for nature’s ingenuity, respect for the magnitude and wisdom of the forces that shape it, and gratitude for having had the opportunity to see and even touch it firsthand.”
Why it matters: This discovery extends our knowledge of subterranean ecosystems and raises new questions about how non‑social spider species can coordinate and persist in large communal webs when resources are plentiful. The find may prompt further research into genetic isolation, reproductive timing, and ecological interactions in cave environments.