[Animals] What if certain animals need agriculture before humans?

[#Wittels-]

Gophers (or pocket rats) fertilize and harvest underground root fields. Some considering this to be a form of agriculture.

A gopher from the southeast finds a place to dig soil while digging. The roots that these moles find while digging do not provide them with enough food. But by harvesting root crops over time, he gained enough energy to keep digging and survive underground.

 

Humans are not the only animals that practice agriculture. Leafcutter ants, for example, painstakingly carry leaves back to their nest to grow a fungus on which they feed. Some beetles also breed fungus inside rotting trees. Damsel fish take care of the areas where their favorite algae grow and eliminate the undesirable ones.

Now researchers have found evidence that small mammals called pocket gophers - a mole-like rodent that inhabits North America - also manage, fertilize and harvest roots for food. This fits the definition of agriculture, according to researchers in a study published July 11 in Current Biology.

"The gophers are shaping the plants as well as the soil," says Francis (Jack) Putz, a professor of biology at the University of Florida (United States) and a researcher on this project. "So they're managing crops. If agriculture is managing crops, that's what they're doing."

While more work needs to be done to definitively show that this behavior amounts to a type of farming or "farming," the finding raises fascinating questions about the ecological role of these creatures and suggests that plant-animal interactions are often much more complex than expected. what was thought It also shows that pocket rats (Geomys), more than pests, are ecological engineers.

 

underground specialists
Southeastern gophers (Geomys pinetis) spend most of their lives alone, burrowing underground. Although they are common in the prairies of North and Central America, it is unlikely that you will see one: their presence is only noticed thanks to the mounds of sandy soil they leave after excavating underground tunnel systems that extend more than 150 meters, usually at about 127 centimeters below the ground.

Their anatomy is adapted to this type of life: they can close their mouths behind their incisors and use their teeth to dig without swallowing dirt. Fur-lined pockets on either side of the face carry seeds and plant material as they plow. Recent research has found that they also glow in the dark, another ability that comes in handy when they live in the deep, perhaps for communication or evading predators.

Until now it was expected that these rodents fed mainly by chewing on the roots they encountered while building new tunnel systems. However, digging tunnels is energetically expensive (up to 300 to 3,000 more tiring than walking on the surface) and researchers show that eating only the roots found while digging does not compensate for the energy expenditure.

 

"If you were to dig a meter and find that many roots in that meter, would you get enough energy from those roots to offset the cost of digging that meter?" asks Veronica Selden, the University of Florida student researcher behind this study. . "In all but one of the cases we looked at, the answer is no."

Research on these rodents
To understand how else these mammals gain access to enough roots to survive, Putz and Selden observed the behavior of moles in a North Florida longleaf pine savanna. The researchers manually excluded moles from parts of their tunnel systems using an open barrel during a small dam, cutting off access to parts of their home for varying amounts of time. They observed that, in the dark and moist underground tunnels that the tozas had dug, new soft and digestible roots grew as stalactites and stalagmites that covered the surfaces.

Scientists say that pocket rats seem to care for the roots to ensure their growth. By maintaining and defending these long tunnel networks, gophers are creating the perfect moist environment for roots to thrive, and causing soil aeration by loosening the soil in which the plants grow in the first place.

In addition, moles spread and distribute their feces and urine through the tunnels.

 

These residues fertilize the soil and the roots, says Selden. This is quite different from other mole species, which often have designated wishing areas, and from other surface herbivores that may incidentally fertilize patches of grass or brush with their droppings.

"Gophers appear to employ a version of a food production system by providing this optimal space for roots to grow," says Selden.

By nibbling on the roots, gophers also appear to be encouraging new growth.

"You are a small mammal and you find yourself with a large root, and death, but it is not very digestible because it has a lot of lignin or cellulose, it is tough, it is hard," says Putz. "But in response to being mowed down, that root will make a lot of little roots, and those will be really tasty and more digestible."

The study found that the moles' daily root crop can supply between 21 and 62 percent of their caloric needs, accounting for the rest of the calories the animals need to continue digging tunnel systems.

"They have these long tunnels that [can't] be explained. Tunneling is risky... energetically expensive," says Putz. So why do it? If not to "grow food," he says, "I can't think of any other reason."

 

The debate on "farming
"He often thought of gophers as 'farmers,'" says Brittany Brito, a habitat biologist with the Wyoming Department of Fish and Game, who was not involved in the study. "I think this [is] a compelling argument that pocket rats might prefer farmer because they aerate the soil, increase nutrient mineralization, and fertilize the soil. Those activities are, in a sense, crops [that they] eat."

But other researchers question whether "farming" is an appropriate term for these rodents' activities.

"I'm not sure if they're actively 'caring' or just actively harvesting for the effect of stimulating growth. It's a subtle difference," says James Demastes, a biology professor at the University of Northern Iowa who studies pocket gophers but did not participate in the work.

He notes that the observations of fertilization are interesting and "definitely unusual" for this family of animals, but the idea that these small rodents could be practicing agriculture resonates with what is known about gophers in general. "I think it's very interesting," says Demastes.

However, the gophers are not seeding or clearing their crops, two items traditionally considered necessary for agriculture and thought to be done by other "farming" animals such as ants and fungus inoculating beetles.

"Describing gopher activity as farming seems like an exaggeration," says Kimberly Asmus Hersey, Mammal Conservation Coordinator for the Utah Division of Wildlife Resources, who was not involved in the study. "I don't see it as that different from a lot of other plant-herbivore interactions."

Add that there are many instances where grazing can stimulate plant productivity, so you don't find this much different than a deer can a bush.

 

It is controversial to say that these rodents farm because people have different definitions of the term agriculture, according to Putz. "They are definitely agricultural engineers because they do everything they can to improve crop growth."

Of course, the researchers point out that there are other ways that gophers might meet their energy needs that have yet to be fully explored. These rodents could search for food in areas with more roots than those analyzed; could rely heavily on tubers for nutrition, in addition to roots; or they might occasionally eat above ground as well, or pull plants underground by their roots and eat them whole.

Although gophers are normally thought of as pests, studies have shown that they are often highly valuable ecosystem engineers for the habitats they inhabit. For example, they have been shown to help maintain grasslands and mountain meadows by keeping out large numbers of tree seedlings, and even helped colonizing plants gain a foothold in the arid landscape that followed the eruption of Mount Santa Helena, in Washington state, in May 1980.

“Knowing that gophers themselves are farmers … flipping the narrative from them being agricultural pests to being agricultural partners that we can learn from,” says Selden.

 

Link: https://www.nationalgeographic.es/animales/2022/07/y-si-ciertos-animales-descubrieron-la-agricultura-antes-que-los-humanos