For the first time in history, scientists have recorded evidence of non-human animals exchanging commodities for different types of favors, a new study in Current Biology reports.
The human ability to trade different goods is considered one of the core traits of our species. However, the new study — conducted by researchers at University of Bern — shows it is not unique to us. Rather, Norway rats also exchange different items, and even work with different “currencies,” such as grooming or food.
Humans cooperate on a daily basis, but such behavior is not only seen in our species. A wide range of animals cooperate. For instance, bees help each other manage their hive, and termites work to construct a mount. Even so, human cooperation is different because it follows a reciprocal strategy of “you help me, I help you.” Scientists believe the reason for that is because reciprocal cooperation is cognitive demanding, especially when commodities get involved.
To challenge that, the team in the study tested whether or not common Norway rats engage in trading of two different forms of help. They tested that with both grooming and food provisioning. To cause the rats to groom, the team applied saltwater to the back of the rodents’ necks in a place where they would need help, and for provisioning they allowed rats to drag food items to each other and recorded how they reacted.
Throughout the research, the test rats more often groomed partners who gave them food and they donated food more to the rats that groomed them. In that way, they traded two services with each other.
This new information could change the way scientists view trading in animals. The team next plans to look beyond rats to see if any other species work in similar ways.