Leafcutter ants invented agriculture 50 million years before humans.
JournalScience journalShare →
Leafcutter Ant
Atta cephalotes
Run the world’s oldest farms. Domesticated a fungus 50 million years ago. Excellent at chemistry.
Curated and rated by Sheriff Six-Legs and The Wild Pest field team · Six Legs Score™ (81/100, Outlaw tier) · Published Apr 25, 2026 · Updated Apr 28, 2026 · Released CC BY 4.0
81Six Legs
Six Legs Score™
81 / 100
Leafcutter ants run the world's oldest agricultural economy — colonies of millions farming a fungus they domesticated 50 million years ago. They build the second-largest non-human cities on Earth (after termite mounds), fight off mold with antibiotics they cultivate, and remove a quarter of the leaves of some neotropical forests.
Size
Workers 2–15 mm (size-graded by role)
Lifespan
Workers ~6 months; queens up to 20 years
Range
Mexico to northern Argentina
Diet
Cultivated fungus only — never eats the leaves they harvest
Found in
Underground galleries beneath neotropical forest floors
Field guide
Leafcutter ants in the genus Atta are among the most ecologically dominant insects of the Neotropics. A mature colony of Atta cephalotes can contain 8 million workers and harvest more leaves per day than a cow eats. The ants do not eat the leaves directly — they carry the leaf fragments back to underground galleries where they cultivate a specific cultivar of fungus (genus Leucoagaricus) that the ants and only the ants can grow. The fungus breaks down cellulose; the ants eat the fungus. The relationship is one of the oldest documented examples of agriculture in the animal kingdom — over 50 million years old, predating human farming by 49.99 million years. Leafcutter colonies maintain antibiotic-producing bacteria (Pseudonocardia) on specialized cuticular pouches that suppress parasitic mold (Escovopsis). The colony's underground city is engineered with ventilation shafts, waste-management chambers, and dedicated routes — a feat of social engineering that biologists still study for emergent behavior patterns.
5 wild facts on file
A mature Atta cephalotes colony can contain 8 million workers and harvest more vegetation per day than a cow eats.
AgencySmithsonian Tropical Research InstituteShare →
Leafcutter ants carry antibiotic-producing bacteria on their bodies to keep parasitic mold out of their fungus farm.
JournalNature journalShare →
The fungus Leucoagaricus that leafcutters farm has been bred for so long it can no longer reproduce without the ants.
JournalMycologia journalShare →
A single leafcutter colony can clear-cut an entire tree in 24 hours — and worker columns can be a kilometer long.
MediaSmithsonian MagazineShare →
Cultural file
Leafcutter ants are taught as the canonical example of insect agriculture in every ecology course. Their underground architecture has been excavated and cast in cement to reveal city-scale subterranean structures — the most famous being a 2012 cast of an Atta laevigata colony in Brazil that took 10 tons of cement to fill.
Sources
AgencySmithsonian Tropical Research InstituteBookHölldobler & Wilson — The Superorganism2008
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