Rats Cut Deals and Trade Different Favors With One Another
Rats follows "tit-for-tat" when trading grooming for food, and food for grooming
Posted Feb 05, 2018
Rats play tit-for-tat with one another across different services
Different forms of cooperation are common among many nonhuman animals (animals; scholarly essays can be seen here). Observations of individuals of different species show that favors are paid and repaid, trading usually like with like, such as trading food for food or grooming for grooming among different individuals. However, there haven't been any controlled experimental studies to learn more about how other animals reciprocally trade different commodities and services. This hole in the database has now been filled and we now know that laboratory rats do indeed trade food and grooming among one another. In an essay called "Reciprocal Trading of Different Commodities in Norway Rats," researchers Manon Schweinfurth and Michael Taborsky who work at the Institute of Ecology and Evolution of the University of Bern write, "Hitherto, there is no experimental evidence that animals other than primates exchange different commodities among conspecifics based on the decision rules of direct reciprocity. Here, we show that Norway rats (Rattus norvegicus) apply direct reciprocity rules when exchanging two different social services: food provisioning and allogrooming."
The research paper is available online so here are a few highlights to whet your appetite for more. An apt summary can be found in a brief essay called "Norway rats trade different commodities." Basically, Drs. Schweinfurth and Taborsky were interested in learning if rats trade different forms of help, namely allogrooming (grooming among members of the same species) and food. Rats typically share food and groom one another, but it wasn't known if they'd trade off food for grooming and vice versa. The design of their study is very simple and clever. They write, "In our experiment, 37 dyads of female wild-type rats were tested in four different situations, each consisting of an experience and a test phase (Figure 2). During the experience phase, focal rats experienced their partner as cooperating or non-cooperating in one commodity (either allogrooming, which was induced by applying saline solution to the neck of the focal rat , or food provisioning, which was induced by enabling a potential donor to pull a tray with food into the focal rat’s reach ). During the following test phase, focal individuals were enabled to return the received service to the same partner by using the commodity opposite to the one used by their partner in the experience phase. We recorded the delay until focal rats provided help to their partner for the first time and also recorded how often they helped their partner during the test phase."
The results of this novel study are pretty straightforward and very interesting and important. Specifically, Drs. Schweinfurth and Taborsky discovered that these rats "apply direct reciprocity rules when exchanging two different social services: food provisioning and allogrooming. Focal rats were made to experience partners either cooperating or non-cooperating in one of the two commodities. Afterward, they had the opportunity to reciprocate favors by the alternative service. Test rats traded allogrooming against food provisioning, and vice versa, thereby acting by the rules of direct reciprocity. This might indicate that reciprocal altruism among non-human animals is much more widespread than currently assumed."
Are there fitness consequences of being nice?
Evolutionary biologists are interested in whether or not different patterns of behavior have positive fitness consequences for the animals who perform them. While we don't know much about if and how wild rats trade favors and cut deals with one another using different services, Drs. Schweinfurth and Taborsky note that "rats initiating as much allogrooming as they receive over their lifetime were shown to survive longer . Hence, the reciprocal exchange of different commodities may reflect an evolved, fitness-enhancing behavioral response. Primates have also been shown to live longer when having close bonds with partners that trade favors with them reciprocally ."
While these results showing that rats trade off different services might surprise some people, it's important to remember that rats also display other sophisticated cognitive skills, such as showing regret when they've made a wrong decision and come to recognize what-might-have-been (for more discussion please see "Rats Regret What They Didn't Do: Behavioral Neuroscience"). We also know that rats are deeply emotional beings. The seminal research of the late Dr. Jaak Panksepp showed that rats like being tickled and they laugh. Rats also display empathy (please also see "Empathic Rats Free Known Trapped Rats From Being Restrained" and links therein).
Rats aren't "animals" according to the Federal Animal Welfare Act
Despite rats displaying highly sophisticated cognitive skills and experiencing rich emotional lives, they get little to no protection from the U. S. Federal Animal Welfare Act (AWA). Indeed, they're not considered to be animals. You may think this is a bad joke, but it isn't at all. For instance, here is a quote from the federal register:
"We are amending the Animal Welfare Act (AWA) regulations to reflect an amendment to the Act's definition of the term animal. The Farm Security and Rural Investment Act of 2002 amended the definition of animal to specifically exclude birds, rats of the genus Rattus, and mice of the genus Mus, bred for use in research" (Vol. 69, no. 108, 4 June 2004).
It may surprise you to learn that birds, rats, and mice are no longer considered animals, but that is the sort of logic that epitomizes federal legislators. Try explaining this alt-fact to a youngster. Researchers are not allowed to abuse "real animals," so the definition of animal is simply revised until it refers only to animals researchers don't need. Garet Lahvis, a behavioural neuroscientist at Oregon Health & Science University in Portland, correctly notes, "We study animals to see what makes us uniquely human, but the findings of empathy in animals often force uncomfortable questions about how humans treat animals." Not granting birds and rodents much more protection from abuse is inexcusable.
Where are all the scientists who know this is pure fiction? Where have they gone? Why aren't they doing something about this inane claim? Most likely, because it works for them (for more discussion of how lame the AWA is, please see "The Animal Welfare Act Claims Rats and Mice Are Not Animals"). If those who draft the revisions of the AWA don't listen to the very researchers who have done the research on the cognitive and emotional lives of these sentient beings, they surely won't listen to non-researchers. And, right now, they don't listen to anyone, perhaps because enough researchers simply have not said "enough is enough," rats, mice, and other non-animals are animals.
It's essential that we use what we know about them on their behalf and fill in what Jessica Pierce and I call the "knowledge translation gap" in our book The Animals' Agenda: Freedom, Compassion, and Coexistence in the Human. The knowledge translation gap refers to the practice of ignoring tons of science showing that other animals are sentient beings and going ahead and causing intentional harm in human-oriented arenas. On the broad scale, it means that what we now know about animal cognition and emotion has not yet been translated into an evolution in human attitudes and practices.
Please stay tuned for more on the fascinating lives of other animals. What an exciting time it is to study and to learn more about the cognitive and emotional lives of nonhuman animal beings. Who'd have ever thought that rats do and feel the things they do?
Steiner, A. P. and Redish, D. (2014). Behavioral and neurophysiological correlates of regret in rat decision-making on a neuroeconomic task. Nature Neuroscience, June 8, 2014. doi: 10.1038/nn.3740.