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Rats Choose Caring Over Chocolate

Last updated:

December 12, 2011

A new study in Science shows that rats might be more compassionate critters than we give them credit for.

According to the Christian Science Monitor, researchers gave pairs of rats two weeks to become friends, and then placed them both in an enclosed arena. One rat from each pair was allowed to move around freely, while the other was placed in a transparent plastic tube that could be opened only from the outside.

Not surprisingly, the rats in the tube showed signs of distress, and the other rats picked up on the emotion. While a rat's typical response is to freeze when frightened, the rats in this study eventually overcame that fear and figured out how to free their trapped companions. Soon, the rats were breaking their buddies out of jail as soon as they were placed in the arena.

"When the free rat opens the door, he knows exactly what he's doing "” he knows that the trapped rat is going to get free," said Peggy Mason, the study's lead author and a neuroscientist at the University of Chicago. "It's deliberate, purposeful, helping behavior."

Researchers then took the experiment one step further and offered the free rats a tempting pile of chocolate chips locked in a second container. A follow-up article in the Christian Science Monitor reports that most rats freed their companions before going for the chocolate, and some rats actually pulled the chocolate out of its container, freed their companions, and shared the goodies with them, "almost as if they were serving them chocolate," said Mason.

(Perhaps a little less surprisingly, the New York Times reports that female rats consistently helped their trapped partners, while males occasionally took the day off.) highlights some of the controversy around the story -- are rats really altruistic, or are they just trying to relieve their own anxiety at being near a distressed friend? -- but one thing is certain: Whatever the motivation, rats care more about helping their friends than winning the rat race.