Scientists mindblown after discovering underground ant city 'equivalent to the Great Wall of China'

Editor's note: This article was originally published on November 4, 2022. It has since been updated.

In 2012, scientists found a sophisticated underground ant city that was once home to millions of insects, later captured in the documentary "Ants: Nature's Secret Power." The massive underground roadways, pathways and gardens of the deserted megalopolis were unearthed in Brazil. One of the largest ant colonies in the world is thought to have existed there, according to DailyMail. The enormous network of tunnels in Brazil previously housed leafcutter ants. These leaf-chewing organisms are the second most complex communities on Earth, after humans. Before starting her colony, an ant queen gathers 300 million sperm from males. Her spawn will then start building and gathering vegetation; their function and part in the ant society will depend on their size. The ant colony, which has been called a "superorganism" for the way it organizes itself, undertook the Herculean task of building its enormous house. But no one is certain exactly when this leafcutter colony disappeared or what killed them.

Experts poured about 10 tonnes of concrete into holes on the surface that the ants used as air conditioning ducts, in order to reveal the tunnels. The process of pouring the material down the maze-like tubes, which covered an area of 500 square feet and reached 26 feet below the surface, took ten days. After a month, scientists under the direction of professor Luis Forgi started excavating and found the amazing metropolis, which has been dubbed the "ant equivalent of the Great Wall of China." 

According to the Nature's Secret Power documentary, they dug out about 40 tonnes of the earth altogether to build the labyrinth. Each insect would have regularly carried loads of earth that would have weighed several times more than the ant, covering a distance that, in human terms, would have been just over half a mile. The resultant megalopolis was extremely efficient. The network allowed for efficient transportation and optimum ventilation, with numerous highways connecting the main chambers and secondary roads found off the main paths. Paths diverge from there and lead to numerous garbage dumps and fungal gardens, which are cultivated from the vegetation gathered by the worker ants.

The plant matter is used to generate fungus, which feeds itself on leaves and supports ant larvae. Waste management will be the only responsibility of other ants. These are usually the older or more disposable members of the community. They move the garbage outside of the city after storing it in dumps. They are specifically in charge of getting rid of harmful parasites like the phorid fly.

By placing its eggs in the cracks of the worker ants' heads, this insect plants the seeds of its doom. Majors are larger ants that act as an organized army and are utilized to fend off such threats. Similar to the armed forces in human nations, they occasionally assist with engineering undertakings like tunnel digging.

Joe Parker, assistant professor of biology and biological engineering, whose research focuses on ants and their ecological relationships with other species, told Science Direct. "It's been a mystery in both engineering and in ant ecology how ants build these structures that persist for decades," Parker says. "It turns out that by removing grains in this pattern that we observed, the ants benefit from these circumferential force chains as they dig down."

When asked if ants are aware of what they're doing when they dig and build these complex structures, Parker calls it a behavioral algorithm. "That algorithm does not exist within a single ant," Parker says. "It's this emergent colony behavior of all these workers acting like a superorganism. How that behavioral program is spread across the tiny brains of all these ants is a wonder of the natural world we have no explanation for."