Scientists have discovered what may be the largest spider web ever found in a cave， spanning an impressive 106 square meters and inhabited by over 111，000 spiders. This subterranean arachnid metropolis， residing in perpetual darkness， evokes images akin to the mythical “Spider Silk Cave” from Chinese folklore.
(For those with arachnophobia， rest assured， the spiders themselves are not depicted as frightening. The sheer scale and endless expanse of the webs create an intentionally awe-inspiring， perhaps slightly unsettling， atmosphere.)
Published on October 17， 2025， in the journal “Subterranean Biology，” a research paper details the discovery of a colossal spider nest within a sulfurous cave situated along the border of Albania and Greece.
The nest is located approximately 50 meters from the cave entrance， in an area devoid of sunlight. The intricate web extends along narrow passages and adheres to the cave walls， creating a continuous expanse of white silk. It’s not a single layer; in some sections， the sheer weight of the accumulated silk has caused it to detach from the cave surfaces.
This scene bears a striking resemblance to cinematic portrayals of adventurers stumbling into the lair of monstrous spiders – a completely dark environment， ubiquitous webs， and a structure larger than a house， all contributing to a deeply unnerving experience.
Detached spider silk remnants.
Fortunately， this immense subterranean “spider city” is not the solitary creation of one gargantuan arachnid.
Scientists estimate the population within this unique ecosystem to be around 111，000 spiders. Genetic analysis further reveals the presence of multiple species， including 69，000 individuals of the house spider (Tegenaria domestica) and 42，000 of the vagrant spider (Prinerigone vagans).
The vast 106-square-meter web complex is actually a mosaic formed by thousands of individual funnel webs.
Discovery of the hidden cave “spider city.”
The initial discovery of this spider habitat occurred in 2022 when geological scientists， while exploring the sulfurous cave， unexpectedly encountered the spider aggregation.
Zoological scientists were then called in， and years of dedicated research on this cave system have led to the current findings.
While the sheer size of the cave dwelling spider web is remarkable， it is not the most significant aspect of this discovery. Researchers are particularly fascinated by the survival strategies of the spiders within the cave and， more importantly， how different species coexist peacefully.
House spiders， belonging to the family Agelenidae， are known to be predatory. Based on prior knowledge， scientists believed that Tegenaria domestica would prey on Prinerigone vagans.
However， within this cave， not only do the house spiders refrain from harming the vagrant spiders， but both species coexist harmoniously. This is an exceptionally rare observation， marking the first documented instance of such interspecies coexistence among spider populations.
The question arises: how do these spiders survive in such a harsh environment， characterized by darkness and high concentrations of hydrogen sulfide gas?
The key factor identified by scientists is the abundant food supply within the cave.
The cave’s rich sulfurous composition supports a large population of sulfur-oxidizing bacteria， which form sticky biofilms in certain areas. These biofilms are a preferred food source for midge larvae. The increased presence of midges， in turn， provides a substantial food source for the spiders.
With ample food and easy prey， the two spider species have no need for inter-species conflict. They have collectively developed a self-sustaining and complete food chain within the dark confines of the cave.
Achieving this level of ecological integration， however， has required significant adaptation from the spiders.
Comparative genetic analysis between cave-dwelling and surface-dwelling spiders revealed that the cave spiders， due to prolonged geographic isolation， have undergone genetic modifications to adapt to the cave’s unique environment.
Concluding Remarks
Strictly speaking， this discovered spider web may not be the absolute largest in the world; rather， it is the largest found within a cave environment. Previously documented spider webs on the surface have been considerably larger.
In 2018， a 300-meter-long spider web was observed on a Greek beach， completely enveloping coastal vegetation. This web was attributed to a species of spider from the family Tetragnathidae.
The reason for such extensive web construction in that instance is attributed by scientists to a confluence of favorable conditions: “timing， location， and abundant prey.”
At that time， it was the spiders’ breeding season. The high temperatures and humidity along the Greek coast supported a prolific insect population， prompting these spiders to congregate and build their webs along the shoreline， creating optimal conditions for reproduction.
However， this phenomenon is transient. Once the next generation matures， these webs naturally decay， unlike the continuously established spider populations in caves.
Let’s take a moment to admire other notable examples of spider web artistry:
In 2024， at the foot of a mountain in Dehua， Fujian， a “spider web ball” estimated to be over 30 square meters was found， densely covered with caterpillars.
In 2021， following floods in Victoria， Australia， native wandering spiders constructed “silk blankets.”
These spiders attempted to escape the rising floodwaters by “ballooning” to higher elevated areas to build their webs.
In 2012， also in Australia， spiders collectively engaged in a mass “ballooning” event for survival.
Ballooning is a method of “flight” for spiders， where they release a strand of silk into the air and are carried aloft by the wind， as depicted below:
