When it comes to farming, termites are OG. By searching through cliffs in southwestern Tanzania, researchers have discovered fossilized "fungus gardens" created by termites 25 million years ago, reports The Washington Post. And the scientists are not kidding about this — the gardens revealed that these ancient termites cultivated fungus by arranging them along a complex plan and feeding them pellets of plant material. Because of this, the researchers say this is the oldest physical evidence of agriculture on Earth.

So, what the heck is a fungus garden?

Well, some termite species cultivate fungi in underground chambers. The insects do this by feeding the fungus with pellets of pre-chewed plant material that the termites can’t digest themselves. Then, the termites wait for large mushrooms to grow out of the fungus spores so they can eat them. But that’s not the only way they get their nutrition. The termites also get to eat the plant material that the fungus converts into a digestible source of food.

It’s this relationship that makes the study, published this week in PLOS One, so interesting. When the researchers analyzed the fossilized fungus gardens, they found that the fungus species only grows when it’s cultivated. So, the finding means that termites and the fungus were working to maintain each other’s species millions of years ago.

"It captures a record of the evolutionary coupling of termites and fungus ... and allows us to trace back the antiquity of this symbiotic relationship," Eric Roberts, a geologist at James Cook University in Australia and a co-author of the study, told The Washington Post.

Termite farms were discovered in Tanzania’s Rukwa Rift Basin. The nests contained small chambers filled with fossilized fungus and really old pellets of fungus food. The researchers were able to confirm their age by comparing their condition to the 25-million-year-old rock surrounding them. Because of this, the researchers say that the gardens demonstrate the intelligence of social insects. Having fungus convert plant material into high-quality food probably gave termites a big leg up, evolutionarily speaking. In fact, this form of agriculture likely played a role in the termite’s migration out of Africa and into Asia — which, interestingly, is similar to the reason humans were able to increase the range of habitats they could inhabit millions of years later.