Rats' bad rap: Study shows them nice, not naughty

December 8, 2011 - 4:36 PM
Nice Rats

This undated handout photo provided by the journal Science shows the presence of a rat trapped in a restrainer elicits focused activity from his cagemate, leading eventually to door-opening and consequent liberation of the trapped rat. Rats, despite their selfish reputation, don't act like, well, rats, new experiments show. Instead, rats show empathy, helping freeing trapped fellow rats, often before gorging on yummy chocolate that they could hog all by themselves. A study of rats in Thursday's journal Science shows that 23 of 30 rats opened a cage to free a trapped rodent. Some of them even did that before eating chocolate chips left out for them and instead shared the goodies with the free rats. (AP Photo/Science)

WASHINGTON (AP) — Rats don't always act like, well, rats.

New experiments show rats demonstrating compassion and helping other rodents. It's a trait some scientists thought was reserved only for humans and higher primates.

And it's certainly not the sneaky, selfish rap that goes with calling someone a dirty rat.

In repeated tests, rats freed another trapped rat in their cage, even when yummy chocolate served as a tempting distraction. Twenty-three of the 30 rats opened the trap by pushing in a door. The rats could have gobbled the chocolate before freeing their partners, but often didn't, choosing to help and share the goodies.

"Basically they told us (freeing another rat) is as important as eating chocolate," said study author Peggy Mason of the University of Chicago. "That's a very striking thing."

In some cases, the rats first took the chocolate chips out of a container, but didn't eat them, then freed the other rat and shared "almost as if they were serving them chocolate," Mason said. The research is reported in Thursday's journal Science.

Also, females showed more consistent empathy than males, Mason said. All six females freed their trapped partner; 17 of the 24 males did so. This confirms other studies that show females demonstrating more pro-social behavior than males, she said.

There were days when the male rats took the day off from helping their trapped partner, but the females never did, she said.

Jeff Mogil at McGill University in Canada, who wasn't part of the study, said it was a tad surprising but even more convincing.

"It's a very, very obvious demonstration of the phenomena," Mogil said. Both scientists said social empathy is probably a characteristic that is important in the evolution of animals.

Mason joked that if rats can be so caring and helpful "there's a sense of optimism. It's something we could be."

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Online:

Science: http://www.sciencemag.org