by Rats have an unfortunate tendency to enjoy living where people live. That’s how a biologist tried to explain people’s hatred of the rodents in a TV news feature about rats gnawing electrical cables in parked cars in the town of Malmö in southern Sweden.
The brown rat, Rattus norvegicus, one of the species best adapted to modern society. These rats followed people around the world to become one of the most abundant mammals, spreading from their native distribution in northern China and Mongolia and reaching Europe in the 1500s, perhaps even earlier. Black rats, however, arrived in Europe as early as the 1st century AD.
Today almost all wild brown rats are synanthropic, meaning they live in close association with humans, eating our leftovers and using human structures for shelter. The relationship between rats and humans is equality, a word that comes from the Latin term “commensal”, meaning “eating at the same table”.
For centuries, rats have been cast as the dark shadow of humanity. Rats have had a huge impact on human civilization, especially through the spread of disease. They have long been associated with dirt, death and destruction. In medieval Europe, people hated rats because of their so-called brutishness, boundless sexual appetite and promiscuity. But their sheer numbers and adaptability reflect man’s evolutionary success.
They have spread with European wars and imperialism to colonized territories in the Americas as well as Africa and Australia. Rats thrive in the trenches of modern warfare even today.
A social and empathetic animal
Real rats are far from the despicable creatures they are often made out to be. Several studies have shown that rats have powerful empathy.
These animals can share the emotional state of others, something called emotional contagion in psychology. Research has shown that when a rat sees another rat in distress, the neural structures that are activated in that rat’s brain closely resemble those that are activated in the human brain when they feel empathy for the pain of others.
One experiment showed that other rats will release a rat from an unpleasant cage even if they are not rewarded. And if chocolate treats were given afterwards, the free rat would usually save at least one treat for the catcher.
This selfless behavior comes from the complex social lives of rats in multigenerational family groups. They form lifelong bonds with other rats and share socially learned skills, such as foraging techniques, across generations. This means that rats have a kind of culture.
A 2023 study even showed that rats can imagine places and things that are not in front of them at the time. In experiments it was shown that rats were going through space in their thoughts, which they had previously explored. As in the studies of empathy, researchers showed this by comparing the regions of the rat’s brain that were activated with those that are activated when people think about making their way through places they have visited.
This ability to imagine also suggests that rats have an understanding of the past and the future.
Living and dying with rats
With this in mind, human ways of dealing with rats seem cruel. The most common chemical method of rat control is antivenom, which causes fatal internal bleeding a week or two after a rat has consumed the poison. Since rats are both social and alert, they prefer to sample unfamiliar food and then wait to see if it makes them or other rats sick.
It is called poison shy. With repellents, however, the time between the consumption of the bait and the death of the rat is so long that they do not associate it with their normal feeding habits.
Human motivation to learn about rats was often the desire to kill them. The main experts in wild rat behavior are their exterminators. And yet, the current methods of controlling wild rat populations are not very effective.
Some rats have developed resistance to the poison and are able to eat it and survive. They are difficult to cultivate, and often recolonize the territory from which they were removed.
Global urbanization is likely to only bring humans into closer contact with rats, and killing rats is not ethical today.
Instead, we should consider other strategies, such as those explored by the Urban Rat Project at the University of Helsinki. Here researchers from different disciplines are trying to gain a deeper understanding of conflicts between rats and humans. They are studying the two species and their interactions, hoping for a future with a less bloody relationship between man and rat. The project has noticed that places in urban areas where people feed birds also tend to attract rats – which people then try to eradicate using poison or traps.
Research has also suggested that people tend to develop a more positive attitude towards them due to more knowledge about rats and their behaviour. More information is therefore needed on the social behavior of wild rats. And people need to manage their own behavior to avoid conflict with rats.
A good place to start is to reduce food waste and stop leaving leftovers unfortified. Fewer rats around human food sources, for example, and more knowledge of their behavior would mean less risk of disease spreading from rats to humans, and from humans to rats.
The future of humanity lies with the rat, a social and empathetic animal. So it’s time to understand our shadows.
This article from The Conversation is republished under a Creative Commons license. Read the original article.
Tobias Linné does not work for any company or organization that would benefit from this article, he does not consult with, shares in or is funded by any company or organization that would benefit from this article, and he has not disclosed any relevant affiliations beyond his academic appointment.
