Pocket gophers go for a pocket-sized harvest by “farming” roots underground

If by reading this headline you hoped to see cute pictures of little burrowing rodents holding pitchforks and hoes, I am sorry to disappoint. But scientists have found evidence of “farming” among pocket gophers.

Living solitary, underground lives in the North and Central American grasslands, pocket gophers spend a lot of their time gnawing away at roots for food. It’s estimated that roots supply 20 to 60% of the pocket-sized rodents’ energy.

In research published in Current Biology, a team of scientists presents the case that not only do the little critters eat the roots, but they also farm the roots that grow in their tunnels.

The authors argue that the gophers might be considered farmers because they provide conditions that favour root growth. The busy gnawers spread their own waste as fertiliser before harvesting or cropping the roots.

Now, it is hardly industrial agriculture or seed germination, but the authors still believe that the gophers have stumbled upon a food production system that qualifies as farming – and the feisty hermits’ tunnels act like crop rows.

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“It really depends on how ‘farming’ is defined,” says co-author F. E. “Jack” Putz from the University of Florida, Gainesville.

“If farming requires that crops be planted, then gophers don’t qualify. But this seems like a far too narrow definition for anyone with a more horticultural perspective in which crops are carefully managed — such as fruit trees in forests — but not necessarily planted.

“With this perspective, the origins of agriculture included Mesopotamian annual cereal and pulse crop cultivation as well as maize cultivation in the Americas, but many cultures around the world developed agriculture based on perennial crops, many of which they didn’t plant but did tend.”

In fact, the root cropping may even be a deciding factor in the gophers’ digging and maintenance of such extensive tunnel systems.

Gopher pulls an entire plant down by the roots into its tunnels. Credit: Norm Douglas.

“Pocket gophers are great examples of ecosystem engineers that turn over soil, thereby aerating it and bringing nutrients back to the surface,” says Putz. “They eat only roots, some of which they grow themselves, and seldom interfere with human activities.”

If the definition of farming checks out in their favour, then gophers will be the first non-human mammal observed to farm.

“Southeastern pocket gophers are the first non-human mammalian farmers,” Putz declares. “Farming is known among species of ants, beetles, and termites, but not other mammals.”

The authors write: “Whether or not [pocket gophers] qualify as farmers, root cultivation is worth further investigation.”

Pocket gopher digging. Credit: Veronica Selden.

And there is further study to be done. The researchers say that future research may reveal whether gophers eat fungi.

Another avenue of future studies could look at seasonal variation in the energy levels that the roots growing into tunnels can provide gophers, and how this relates to the rodents’ activity cycles. At this stage, it’s unclear how the underground cultivation of roots by the gophers affects vegetation at the surface.

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