Do Gophers … Farm?
Step 1: Dig tunnel. Step 2: Cultivate roots. Step 3: Profit.
Of all the rodents that Elizabeth Parsons has worked with—among them, mice, rats, and squirrels galore—pocket gophers are “probably the feistiest,” she told me. Aboveground, they’ve got a bad rap for mangling gardens and golf-course greens with their characteristic sandy mounds, and when they’re provoked, they gladly put up their dukes. “They will charge you, even though you are human-sized and they are about the size of a russet potato,” Parsons, a wildlife ecologist at the University of Georgia and the Jones Center at Ichauway, said.
And that’s nothing compared with what goes on underground. The rambunctious rodents spend nearly their entire life excavating and maintaining a series of labyrinthine tunnels that can stretch several hundred feet, where fresh air is scarce and the humidity can reach 98 to 100 percent, says Veronica Selden, a biologist at the University of Florida. Apart from the initial venture that takes gophers out of their mother’s nest, the annual foray males make to mate with females in adjacent lairs, and quick surface trips to dump excess soil, gophers pretty much never leave their underground abode. They eat, sleep, defecate, procreate, and eventually die beneath the same inches of packed dirt, essentially occupying their own grave from adolescence on—all the while toiling, toiling, toiling to keep their dug-out digs in tip-top shape.
A couple of years ago, Selden, then a student in an undergraduate course taught by the ecologist Francis “Jack” Putz, became entranced by the little mammals. She started to wonder how gophers were powering their pursuits on a vegan diet, restricted, presumably, to the roots, tubers, and other schmutzy snacks they stumbled across while digging—not exactly the fattiest fodder in the world. When Selden sampled the local Florida soil, she found that if gophers noshed only on these random snippets of vegetation, they’d be in constant calorie deficit and eventually would starve.
So Selden and Putz brainstormed alternative ways the gophers might be sourcing food. Freshly carved gopher tunnels, they realized, are weirdly greenhouse-esque, dense with wet, nutrient-rich air. Maybe local plants could take advantage of this and poke their lowermost bits into the rodents’ soily homes—offering the gophers food not just ahead of where they were digging, in the packed earth, but also behind them, in the open-air tunnels they’d already gouged. Which could be the perfect opportunity to enhance the diets of the denizens within.
To test that idea out, the duo spent months digging on Putz’s property, trying to locate gopher tunnels and measure the ingrowth of roots. That meant keeping the rodents out of their dwelling for a few weeks. Their first efforts, using strips of plywood and metal, “totally failed,” Putz told me. “They outsmarted us. It was a little embarrassing.” Finally, Selden and Putz cordoned off sections of tunnel with sawed-off barrels and began to inspect the grasses, clovers, and other local plants that had shoved their roots inside. There were a lot of them, Putz told me, like stalactites and stalagmites projecting into caves—enough to meet roughly 21 percent of the rodents’ daily nutritional needs, possibly more.
That’s not a total feast; as Parsons, the rodent ecologist, points out, the gophers are probably still supplementing those infiltrating snacks with other foods, including tubers as well as plants from the surface, which the creatures pull down by the roots. But there’s a mutually beneficial tinge to the gopher-root relationship, Selden and Putz said, that feels special. Gopher tunnels are a particularly choice environment for roots to flourish in; the rodents, in turn, reap the nutritional rewards. The partnership may even qualify as “a low-level food-production system,” managed by the rodents like a rudimentary subterranean farm, Selden told me. “They’re creating a space for their crops to grow and then harvesting them” in a way that enhances their diet to a pretty decent degree.
The notion of gophers as farmers is a beguiling one. Few nonhuman animals have earned the moniker, and they’re mostly from marine or invertebrate branches of the tree of life. Limpets fertilize patches of seaweed with mucus trails that ooze out of their feet; brightly colored damselfish keep their gardens of algae healthy by driving out invasive urchins and inviting in friendly crustaceans; sea snails wound grasses and excrete feces into them, fostering the growth of the fungi they like to eat. And one of the world’s most complex agricultural systems may belong to leaf-cutter ants, says Ted Schultz, an entomologist at the Smithsonian National Museum of Natural History who studies the insects. The ants nurture tracts of fungi inside their nests, feeding them slivers of vegetation, anointing them with pesticides, and weeding out foreign molds and bacteria before harvesting their crops. In several partnerships, the ants are totally dependent on their fungi, and vice versa; the two have domesticated each other and can no longer live apart.
Whether gophers earn membership in this 4-H club, though, remains up for debate. Farming doesn’t even have a universal definition among humans, and the semantics only get messier when the concept is applied to other species. But if gophers are prepping soil in a way that enhances root growth, then chowing down on the plants, “you could call that cultivation,” Schultz told me. “I kind of like to think of it as proto-agriculture … as kind of a farming trait.” And that does seem to be the case, at least in the parts of the southeastern United States where Shelden and Putz did their work. Digging claws accomplish a sort of tilling, aerating the soil, “which makes it puffier and easier for plants to grow, and water to infiltrate,” Parsons said. And although some gophers set up cloistered latrines in their tunnels, others may freely scatter their scat about their home, which could give plants a fertilizing boost.
But there’s no evidence that the rodents are planting their crops, as fungus-eating leaf-cutters and typical human farmers do. (To be fair, the mucus-trailing limpets and alga-gardening damselfish don’t seem to be sowing seeds, either.) And it doesn’t appear that the gophers and plants are heavily dependent on each other for survival, or that they’ve been coevolving—criteria that feel much more agriculture-esque, according to Melinda Zeder, an archaeologist at the Smithsonian’s National Museum of Natural History and an expert on animal domestication. The gophers, Zeder told me, are clearly “messing around with the environment. They’re ecosystem engineers.” But to truly bend toward formal farming, at least in her mind, the fates of plant and animal would have to more intricately intertwine.
It’s also unclear just how much intentionality needs to be imbued into a multispecies symbiosis for it to be a proper farm. Schultz and Zeder agreed that it’s not a necessary box to check. But “accidental promotion of plant growth” could be an enormously wide net to cast. “There are so many examples of animals modifying the plants around them” in ways that turn out to be beneficial for both parties, perhaps by happenstance, says Ann Marie Gawel, a conservation ecologist at Iowa State University. If gophers qualify as farmers, what about acorn-caching squirrels, whose hoarding shenanigans sometimes sprout oak trees? What about cows, whose grazing and defecating can stimulate the growth of grass? What about seed-dispersing birds, bats, and aardvarks, whose fruit-chomping habits can scatter plants across tracts of land they’d never otherwise access? Gawel isn’t sure these activities—the gophers’ antics included—are enough to warrant the title of “farmer.” With regard to the rodents, Parsons agrees. “To me, it’s a bit of a stretch,” she said.
Regardless of where on the agricultural spectrum gophers sit, Zeder says she’s convinced that far more animals than humans have appreciated thus far are farming, cultivating, or domesticating in some form. People tend to consider agriculture “the domain of human mastery over nature,” she told me. But the process has roots outside the human realm. People aren’t even the most impressive plant growers out there. Some cultures have hit upon sustainable ways to raise and nurture their crops; others very much have not. Fungus-farming ants, meanwhile, “have been doing this for millions of years without causing the environment to totally collapse,” Zeder said. We can take cues from other creatures, whether or not they’ve earned the blue ribbon at the county fair.