he gophers subsist mostly on roots encountered in the tunnels that the rodents excavate. But the local terrain doesn’t always provide enough roots to sustain gophers, two researchers report in the July 11 Current Biology. To make up the deficit, the gophers practice a simple type of agriculture by creating conditions that promote more root growth, suggest ecologist Jack Putz of the University of Florida in Gainesville and his former zoology undergraduate student Veronica Selden.

But some scientists think it’s a stretch to call the rodents’ activity farming. Gophers aren’t actively working the soil, these researchers say, but inadvertently altering the environment as the rodents eat and poop their way around — much like all animals do.

Tunnel digging takes a lot of energy — up to 3,400 times as much as walking along the surface for gophers. To see how the critters were getting all this energy, Selden and Putz in 2021 began investigating the tunnels of southeastern pocket gophers (Geomys pinetis) in an area being restored to longleaf pine savanna in Florida that Putz partially owns.

The pair took root samples from soil adjacent to 12 gopher tunnels and extrapolated

how much root mass a gopher would encounter as it excavated a meter of tunnel. Then the researchers calculated the amount of energy that those roots would provide.

“We were able to compare energy cost versus gain, and found that on average there is a deficit, with about half the cost of digging being unaccounted for,” Selden says.

Upon examining some tunnels, Selden and Putz saw gopher feces spread through the interior along with signs of little bites taken out of roots and churning of the soil.

The gophers, the researchers conclude, provide conditions that favor root growth by spreading their own waste as fertilizer, aerating the soil and repeatedly nibbling on roots to encourage new sprouting.