A 1,140-square-foot spiderweb in a Greek-Albanian cave houses 111,000 spiders in a rare cooperative colony, researchers say.

A massive spiderweb spanning 1,140 square feet has been discovered in Sulfur Cave on the Greek-Albanian border, housing over 111,000 spiders of two species, Tegenaria domestica and Prinerigone vagans, in a rare cooperative colony. The web, formed in a dark, sulfur-rich cave powered by chemosynthetic bacteria, represents the largest known spiderweb and the first documented case of these typically solitary species coexisting. Researchers say the extreme environment, lacking light and rich in hydrogen sulfide, likely reduces predatory behavior, enabling the colony’s survival. Genetic analysis shows adaptations to the harsh conditions. The discovery, first made in 2022 and published in October 2025, highlights unexpected ecological cooperation and raises conservation concerns due to the cave’s cross-border location.