THE FARMERS WHO BEAT US TO AGRICULTURE BY 66 MILLION YEARS

How Ants Farmed Fungus 66 Million Years Before Humans

Long before the first human pressed a seed into soil, an underground empire had already invented crop cultivation, animal husbandry, and its own antibiotics  and never once needed a chemical spray to do it.

Sixty-six million years ago, a rock about ten kilometers wide struck the Yucatán Peninsula at more than twenty kilometers a second. Three-quarters of all species on Earth died in what followed. Sunlight dimmed behind a curtain of ash, plants stopped photosynthesizing, and entire food webs folded in on themselves.

Somewhere in that wreckage, a small insect made a decision that would outlast the dinosaurs, the Ice Ages, and every human civilization to come. It stopped hunting and gathering. It started to farm.

That insect was an ant. According to a 2024 genomic study led by Smithsonian entomologist Ted Schultz and published in the journal Science, this is close to the moment fungus-farming ants began cultivating their first crops  in the aftermath of the very extinction event that eventually cleared space for mammals like us. Humans didn't domesticate our first crops until roughly 12,000 years ago. Ants got there first. By a factor of more than five thousand.

And fungus is only half of it. Somewhere on a rose stem right now, a completely different ant species is milking livestock.

Ants, it turns out, invented both agriculture and animal husbandry  independently, competently, and without holding a single meeting about it. Despite weighing less than a raindrop, they built the whole apparatus: specialized labor, pest control, and a working supply chain. Let's look at how.

THE GARDENS BENEATH THE RAINFOREST

Walk through a rainforest in Costa Rica or Brazil and you'll likely cross a highway. Not a paved one. A living one  a column of ants marching in single file, each hoisting a disc of green leaf several times its own size overhead, like a parasol.

Early naturalists nicknamed them exactly that: parasol ants. Their real name is leafcutter ants, genus Atta and Acromyrmex, and what looks like harvesting is closer to grocery shopping for somebody else entirely.

Here's the strange part. The ants never eat the leaves. Not directly, anyway.

Back in the nest, workers chew the leaf fragments into a wet pulp and pack it into underground chambers, seeding it with droplets of their own fecal fluid, which carries enzymes recycled from their crop. This pulp isn't food. It's compost  the growing medium for a fungus called Leucoagaricus gongylophorus, a species that grows nowhere on Earth except inside ant nests.

The ants tend that fungus the way a serious gardener tends a greenhouse. Colonies regulate temperature and humidity inside nests that plunge several meters underground and branch into hundreds of separate chambers, holding conditions inside the fungus's narrow comfort zone. Workers weed out contaminating molds by mandible, prune unwanted growth, and keep the compost coming.

In return, the fungus manufactures something found nowhere else: gongylidia, swollen, nutrient-dense tips of fungal thread that cluster into grape-like bundles called staphylae. This is the colony's staple food, for adult workers and for the larvae developing in nursery chambers alike. A single colony, which can include several million ants, survives entirely on a crop it grows from nothing but leaves and its own enzymes.

Growing one crop, in one place, for tens of millions of years sounds like an invitation for disease. Any farmer will tell you a monoculture is a gamble. Ants solved that problem before humans had a word for it  and they solved it with their own bodies.

Many leafcutter workers carry a bacterium called Pseudonocardia in specialized patches on their exoskeleton. It produces antimicrobial compounds that suppress Escovopsis, a parasitic mold that specializes in nothing but invading these ant-tended fungus gardens  an arms race that researcher Cameron Currie and colleagues have documented since the late 1990s, and estimate at roughly 50 million years old. The ants carry a second chemical defense, too: glands on their thorax secrete myrmicacin, an antibacterial acid that helps keep the whole operation sterile.

Put it together, and a leafcutter nest isn't simply a colony of insects. It's a four-species operation  ant, fungus, bacterium, and the pathogen they're perpetually at war with  running one of the oldest continuously operating farms in the history of life on this planet.

THE ANTS WHO KEEP DAIRY COWS

Not every ant farms mushrooms. Many farm livestock instead  and you've probably watched it happen without realizing what you were looking at.

Look closely at aphids clustered on a rose stem or a bean plant, and you'll often find ants patrolling among them, apparently doing nothing. They are not doing nothing.

Aphids feed by tapping into phloem, a plant's pressurized pipeline of sugar-rich sap. They process far more sugar than they need, and the excess leaves their bodies as a sweet liquid called honeydew. Ants want that honeydew badly enough that they've turned aphids into livestock, a relationship biologists call trophobiosis.

An ant approaches an aphid and taps it rhythmically with its antennae  a gesture entomologists have long compared to milking. The aphid responds by releasing a droplet of honeydew, which the ant drinks on the spot or carries home to the colony. Some aphid lineages that have depended on ants long enough have lost much of their own ability to release honeydew without that tapping. They need the ants now, the way a dairy cow bred for high yield needs a farmer.

In exchange, ants provide protection aphids badly need. Aphids are slow and soft-bodied, easy prey for ladybird beetles and lacewing larvae, both of which treat an aphid colony as an open buffet. Ants patrol their herds, drive predators off, and sometimes haul away a predator's eggs before they can hatch.

Some ants take the analogy further than seems reasonable for an insect. The yellow meadow ant, Lasius flavus, tends a root aphid called Anoecia zirnitsi. Researchers Thomas Parmentier and Nicky Wybouw reported in a 2025 study in Royal Society Open Science that these ants collect the aphids' eggs every autumn, carry them into nest chambers beside their own brood, and groom them all winter  a service that measurably shields the eggs from fungal pathogens and predators until spring arrives. When a host plant runs thin, ants of other species have been seen shepherding their aphids to fresher growth nearby: livestock moved to new pasture.

Selective tending. Milking. Protection from predators. Seasonal relocation. In nearly every functional sense, this is animal husbandry  and ants were doing it long before anyone thought to build a barn.

A FARM WITH NO WASTE

Both operations run on strict division of labor. Among leafcutters, job assignment tracks body size almost exactly: the smallest workers ride along on leaf fragments, guarding against parasitic flies that try to lay eggs on the leaf-cutters' necks; mid-sized workers do the cutting and hauling; the largest defend the nest. Nobody is in charge. Nobody needs to be.

The effects reach well past the nest itself. Leafcutter colonies turn over enormous volumes of soil while excavating chambers meters deep, aerating it and redistributing nutrients much the way earthworms do, only at a rainforest's industrial scale. Spent fungal compost, leaf litter, and dead ants all cycle straight back into the ground as fertilizer. Aphid-tending ants, in turn, help keep aphid populations in a rough equilibrium rather than letting them explode unchecked.

None of it involves a synthetic pesticide, a chemical fertilizer, or a shipment from anywhere else. The inputs are leaves, sunlight, and bacteria the ants already carry on their own bodies. The system has run at scale, across two continents, for tens of millions of years, without collapsing its own foundation.

AN EMPIRE THAT NEVER NEEDED US

It's tempting to reach for a moral here  something about ants shaming us into composting. The more unsettling fact is simpler than any lesson. We didn't invent this. We arrived on a planet where something else had already been farming, breeding livestock, and manufacturing its own antibiotics for longer than primates have existed as a lineage.

And the strangest chapter in that empire may be the one science understands least.

In a handful of tropical ant species in the genus Acropyga, a virgin queen leaving the nest on her mating flight does something no queen bee or wasp does. She clamps a live mealybug between her mandibles and carries it with her  through the flight, through mating, into the burrow where she'll found an entirely new colony alone. That single mealybug becomes the founding member of a livestock herd that doesn't exist yet, for a colony that doesn't exist yet either.

Entomologists call the behavior trophophoresy. They have witnessed it directly only a handful of times in more than a century of study, because it unfolds during brief, unpredictable mating swarms, often at dusk or underground. Nobody has fully documented how a newly winged queen chooses her mealybug, how she keeps it alive through flight and copulation, or how many of these single-mother expeditions simply fail.

She flies once. She carries a species she cannot survive without. And she goes to found a farm nobody ever taught her to run.