Largest animal-built fungi farm

The subterranean nests built by leafcutter ants of the genus Atta from South America can extend 7 metres (23 feet) deep and span tens of square metres, with a single colony playing host to millions of ants. The ants harvest leaves (as much as 12-15% of leaves in some forests), bringing them in to nourish their underground fungus gardens within their air-conditioned nests; the fungus, in turn, serves as food for the ants. In order to better understand the spectacular architectural complexity of these insects' homes, cement is occasionally poured into an abandoned nest to create a cast of the interior. One particular nest, built by Atta laevigata, covered in excess of 67 square metres (721 square feet) and was comprised of 1,920 chambers, 238 of which were occupied by fungus gardens.

An extensive network of foraging trails over the ground lead to entry holes that then lead to another network - a labyrinth of tunnels that function as air vents or transport routes to and from variously shaped chambers that contain the fungus gardens, living quarters and garbage tips (sites for decomposing plant material, dead ants and spent fungus).

Leafcutter ants have been farming for at least 8-12 million years while humans at most have been at it for around 23,000 years, and perhaps only 12,000 years as some experts would have it.