Quid Pro Quo — I’ll do something for you, if you do something for me — isn’t restricted to, well, politics.

Ok, it’s not even restricted to humans or other primates.

Rats do it too.

In exchange for food, rats will “groom” another rat’s hair, sometimes repeatedly in what scientists say is a cooperative behavior similar to humans. Researchers at the University of St. Andrew in Scotland found that rats were more inclined to engage in grooming with a fellow rat when food was received from it than not, and vice versa.

While many different animals show reciprocity for like commodities, such as food for food, primates have been known to be capable of trading goods, i.e. food, for other services, such as sex, for instance, in the case of chimpanzees. Trading of different commodities is considered a fundamental component of human interactions, with quid pro quo a part of our being and how we get along.

The fact that rats do it too indicates that it may be more widespread in nature than originally believed, and the reciprocal trading may not be limited to large-brained species with advanced cognitive abilities.

“The prevalence of reciprocal cooperation in non-human animals is hotly debated,” said Dr. Manon Schweinfurth of the School of Psychology and Neuroscience at the University of St. Andrew in Scotland, co-author of a study on rat behavior. “Our study suggests that either rats have this concept or reciprocity is cognitively less demanding than previously thought.”

She and Professor Michael Taborsky of the Institute of Ecology and Evolution at the University of Bern published a paper ‘Reciprocal Trading of Different Commodities in Norway Rats. on the subject earlier this year in Current Biology.

Quid Pro Quo

For humans, giving something in exchange for something else is a part of interactions with others and starts at a young age. “A key feature of human interactions is the quid pro quo: you do something for me and in exchange I do something for you and in exchange I do something for you,” Jonaton D. Crystal, Department of Psychology and Brain Sciences, Indiana University wrote about the study as a Quid Pro Quo in the journal Current Biology.

“Children 3 years onward reliably reciprocate with each other,” Schweinfurth says. “Kids most likely don’t have to learn reciprocity either but their brain is not fully developed and they lack capabilities that enable them to reciprocate.” “

Quid pro quo has been in the news constantly the last few months — maybe more so than at any time in recent memory — as investigators examine President Trump’s actions in allegedly withholding funds for Ukraine unless that government investigated former Vice President Joe Biden’s son, who conducted business there. ( The Democrats began steering the party’s narrative away from quid pro quo but a more directed allegation of “bribery.”

While quid pro quo is especially the topic of debate for political humans, some scientists believe that the action of reciprocity is definitely human, but others say the practice is not unique to us.

“The prevalence of reciprocal cooperation in non-human animals is hotly debated,” Schweinfurth writes. “Part of this dispute rests on the assumption that reciprocity means paying like with like. However, exchanges between social partners may involve different commodities and services.”

Many animals help each other such as bees managing hives seeking other bees’ assistance. And several species, particularly among primates, such as monkeys, have been known to apply such rules when exchanging food for other actions, such as protection, Schweinfurth says. Primates have been known — through observational evidence — to trade different services, such as chimpanzees trading grooming for meat.

Rats Do It

But rodents, such as rats? Indeed. Her studies show that “rats seem to follow reciprocal rules like tit-for-tat to help each other,” Schweinfurth said. Of rats, “they likely don’t memorize exact donation rates or calculate that was received but form attitudes toward their partner…like partner A was nice to me,” she added.

Rats live in burrows and form mixed social groups that might involve as many as 200 individual rats, which frequently interact with each other. As highly social animals, they often huddle together to keep warm, share food and have been known to softly pat each other’s hair.

“Rats are good model organisms because you can keep them in the lab and they learn quickly how to use experimental setup. We worked not with the classical lab rat but with descendants of wild rats,” the species known as Norway rats, Schweinfurth said.

In a series of experiments, food — oat flakes — were put into a moveable platform and rats pulled it toward other “partner” rats. The rats, which were closely studied, known as focal rats, pulled a stick connected to the moveable platform in a cage and provided food to the partner, which then in turn softly patted or groomed them. Each cage held two rats, each in its own little compartment. By pulling the connected stick, the platform moved into the cage and provided food only to the partner rat.

In an examination of more than 30 rats, the so-called focal rat continually provided more food to grooming partners than not. Rats provided more food to “cooperative” partners in test conditions, which were not previously achieved, Schweinfurth said.

The grooming occurred after saltwater was applied to the neck of the focal rat to create a situation where help was needed. Each rat’s “propensity to help the partner remove the unpleasant saltwater is enhanced by the previously experienced food donations of the partner,” the researchers wrote. “Grooming is a widespread behavior and the results might hence be more generalized to other species,” Schweinfurth said. After the experiment, the researchers took rats out into a large container where they could groom each other.

“Hitherto there is no experimental evidence that animals other than primates exchange different commodities among conspecifics based on the rules of direct reciprocity,” the researchers added in the study. “Here we show that Norway rats apply direct reciprocity rules when exchanging two different social services: food provisioning and (grooming.)

Rats — Lots of Them

Schweinfurth said she has been studying rats since 2013, calling them “fascinating animals.”

“They are highly intelligent and billions live with us, but we really don’t know much about them,” she says. “We have a very different and interesting relationship with rats. They are very useful to us as lab rats. We hate them when we encounter them in the cities and we love them as pets.”

“There is some evidence (from another study) that rats anticipate reciprocity in the future,” she says. “If rats are hungry, they are more likely to invest in donating food to others, probably in the hope of getting more back.”

Despite the give and take, Schweinfurth said she has been restarted in her studies that she couldn’t find a “friendship” among rats.

“For the rats, they work on not an accumulative experience with a partner,” she says. “They respond to the last experience. Basically, they only consider “what have you done for me lately.”

In her recent work, Schweinfurth has moved beyond rats — to humans and other primates.

She said she wanted to “compare rats to understand how unique our form of reciprocity is and whether different species have found different ways to cooperate with each other.”

And much of that cooperation begins with the quid pro quo. – Joe Cantlupe, HealthDataBuzz

(Photo: Rats “grooming.”Courtesy of Dr. Manon Schweinfurth)