We’ve all heard how rats will abandon a sinking ship. But will the rodents attempt to save their companions in the process? A new study shows that rats will, indeed, rescue their distressed pals from the drink—even when they’re offered chocolate instead. They’re also more likely to help when they’ve had an unpleasant swimming experience of their own, adding to growing evidence that the rodents feel empathy.
We’ve all heard how rats will abandon a sinking ship. But will the rodents attempt to save their companions in the process? A new study shows that rats will, indeed, rescue their distressed pals from the drink—even when they’re offered chocolate instead. They’re also more likely to help when they’ve had an unpleasant swimming experience of their own, adding to growing evidence that the rodents feel empathy.
Previous studies have shown that rats will lend distressed companions a helping paw, says Peggy Mason, a neurobiologist at the University of Chicago in Illinois who was not involved in the work. In a 2011 study, for example, Mason and colleagues showed that if a rat is trapped in a narrow plastic tube, its unrestrained cagemate will work on the latch until it figures out how to spring the trap. Skeptics, however, have suggested that the rodents help because they crave companionship—not because their fellow rodents were suffering.
The new study, by researchers at the Kwansei Gakuin University in Japan, puts those doubts to rest, Mason says. For their test of altruistic behavior, the team devised an experimental box with two compartments divided by a transparent partition. On one side of the box, a rat was forced to swim in a pool of water, which it strongly disliked. Although not at risk of drowning—the animal could cling to a ledge—it did have to tread water for up to 5 minutes. The only way the rodent could escape its watery predicament was if a second rat—sitting safe and dry on a platform—pushed open a small round door separating the two sides, letting it climb onto dry land.
Within a few days, the high-and-dry rats were regularly aiding their soaking companions by opening the door, the team reports online today in Animal Cognition. They did not open the door when the pool was dry, confirming that the rats were helping in response to others’ distress, rather than because they wanted company, Mason says. Rats that had previously been immersed learned how to save their cagemates much more quickly than those who had never been soaked, suggesting that empathy drove their behavior, she adds. “Not only does the rat recognize distress, but he is even more moved to act because he remembers being in that situation.”
Continue reading at Science/AAAS.
Rat image via Shutterstock.
