Humans aren’t the only mammal on Earth to farm anymore — pocket gophers do too

The farm mammal family has been joined by the southeast pocket gophers, according to new research.

A display of stuffed pocket gopher at the Pacific Grove Museum of Natural History, Pacific Grove, California, USA. Image via Wikimedia.

Although they cannot plow huge fields or drive combines, pocket gophers (Thomomys bottae), burrowing rodents native to North and Central America, also practice their own type of agriculture. These animals stay one step ahead of their energy-guzzling burrowing lifestyles by actively tending to the root systems that grow through their tunnel networks.

According to a recently published study, ground squirrels get between 20 and 60 percent of their daily energy intake from cultivated roots.

grow their own

“Southeastern pocket gophers are the first breeders of non-human mammals,” said Francis Putz, professor emeritus of biology at the University of Florida, Gainesville, one of the study’s two authors, in a statement. Press. “Agriculture is known in species of ants, beetles, and termites, but not in other mammals.”

“All over the world there are many species of burrowing [i.e. burrowing] mammals with habits similar to those of the southeastern pocket gophers we have studied. Among them may be other farmers,” he added for ZME Science.

Pocket gophers live solitary lives just below the surface of the grasslands of North and Central America. They build vast networks of tunnels in which they reside most of the time, rarely finding themselves above ground. These tunnels are known to serve as shelter and pantries for animals, but it seems that they also serve as a food source.

In an email to ZME Science, Professor Putz explains that the research has been spurred by a “general interest in the natural history of these little-studied beasts”. But the research took on new life when Putz and one of his students, Veronica Selden, the paper’s first author, began doing the heavy lifting needed to actually study these rodents. I asked the professor what first informed them that gophers could farm, and he replied:

“The tunnels are so deep in the ground, well below the depth at which roots abound. By digging ourselves, we were reminded of the energy cost of this activity”.

Gophers don’t just eat roots they find while digging, the authors explain. Instead, they nourish the roots they encounter, providing them with favorable conditions to promote growth. For example, they use their own waste as fertilizer.

“By leaving their urine and faeces in their tunnels, rather than in specialized places (i.e. latrines), the fertilization effect is more widespread,” says Professor Putz for ZME Science.

Unlike the way people farm, gophers prefer to go it alone rather than working together. They are ‘entirely independent’, adds Professor Putz, only being social ‘when they mate, but afterwards they return to their own tunnel system, which they defend against all comers’. This extreme territoriality is a characteristic that distinguishes ground squirrels from most other rodents in general and from other ground squirrels in particular, to which they are related. It is possible that the dependence of ground squirrels on their root crops for survival has fostered this territorial behavior throughout their evolutionary history.

The team argues that because these animals use a system that promotes the growth and development of roots that are then grown or harvested entirely, the southeastern pocket gophers essentially use a system qualified as agriculture.

“It really depends on how ‘farming’ is defined,” says Putz. “If agriculture requires crops to be planted, then ground squirrels are not eligible. But that seems like far too narrow a definition for anyone with a more horticultural perspective in which crops are carefully managed – like fruit trees in forests – but not necessarily planted. From this perspective, the origins of agriculture included the Mesopotamian cultivation of cereals and annual legumes as well as the cultivation of maize in the Americas, but many cultures around the world developed agriculture based on perennial crops, many of which did not plant but serviced. ”

The two authors explain that this root-farming behavior of ground squirrels may explain why they must build, maintain and defend such extensive tunnel networks. These are not just houses or storage spaces that animals expand for no reason – they are akin to crop fields.

For now, the team plans to expand their research to see if ground squirrels also cultivate and eat mushrooms, and to record how seasonal variation in the energy contribution of their cultivated roots relates to their activity cycles. It’s also not yet clear how their underground work affects surface vegetation, another promising avenue of research the team is considering.

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

“One of the motivations for studying pocket gophers is that too many people kill them for no particular reason,” Professor Putz told me. “If you Google ‘pocket gopher’, you’ll see that the web is full of sneaky ways to kill these harmless little animals, from pressure traps to drowning, not to mention various poisons.”

“We hope our discovery of this remarkable behavior will lead more people to understand ground squirrels and leave them alone.”

Besides direct efforts to exterminate them, gophers also come under some pressure from habitat destruction, Prof Putz adds, “but they are quite adaptable, happy in pastures and lawns as well as savannahs and natural grasslands. “. He thinks helping people better understand ground squirrels will help ease some of the pressure they face, because “the first step to nature conservation is to develop an appreciation for nature” – and it all starts by knowing what there is to appreciate.

In conclusion, Professor Putz says he is “delighted to have been part of a discovery with an undergraduate student, working on a project that involved a lot of shovel work but not a big research budget – natural history at the ‘old made in a backyard’.

“The moments of research that I found most endearing were when we failed, sometimes after great physical exertion, but laughed at ourselves and kept digging.

The article “Root cropping by pocket gophers” was published in the journal Current biology.

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