Pocket gophers are underground farmers

Pocket gophers are a species of mammals known to live solitary, underground lives, feeding on roots in North and Central American grasslands. A team of researchers from the University of Florida has found that these animals keep up with their energy demands by “farming” roots that grow into their tunnels, which supply 20 to 60 percent of the gophers’ daily calories.

“Southeastern pocket gophers are the first non-human mammalian farmers,” said study senior author Francis Putz, a professor of Biology at the University of Florida. “Farming is known among species of ants, beetles, and termites, but not other mammals.”

The scientists discovered that gophers don’t just eat roots that happen to grow in the paths of new tunnels that they excavate. Instead, by spreading their own waste products as fertilizers, they provide conditions favoring root growth and then harvest or crop those roots. Although whether such activities qualify as farming is still a matter of debate, Professor Putz argues that they should be considered similar to behaviors seen in humans.

“It really depends on how ‘farming’ is defined,” he explained. “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.”

According to the scientists, root cropping may explain why gophers build and maintain such extensive tunnel systems, which are comparable to rows of crops. “Pocket gophers are great examples of ecosystem engineers that turn over soil thereby aerating it and bringing nutrients back to the surface,” said Professor Putz. “They eat only roots, some of which they grow themselves, and seldom interfere with human activities.”

Further research is needed to investigate how seasonal variation in the energetic contributions of roots growing into tunnels relate to gophers’ activity cycles, and how their underground activities affect vegetation at the surface.

The study is published in the journal Current Biology.

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By Andrei Ionescu, Earth.com Staff Writer