He’s No Rat, He’s My Brother

In the February 25 Issue:

He’s no rat, he’s my brother

Rodents exhibit empathy by setting trapped friends free

By Laura Sanders

December 31st, 2011; Vol.180 #14 (p. 16)

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A rat allowed to roam around eventually figured out how to set free a trapped cagemate. Rats didn’t offer the same courtesy to stuffed animals, suggesting the creatures have empathy for one another.© Science/AAAS

Calling someone a rat should no longer be considered an insult. The often maligned rodents go out of their way to liberate a trapped friend, a gregarious display that’s driven by empathy, researchers conclude in the Dec. 9 Science.

“As humans, we tend sometimes to have this feeling that there’s something special about our morals,” says neuroscientist Christian Keysers at the Netherlands Institute for Neuroscience in Amsterdam, who was not involved in the study. “It seems that even rats have this urge to help.”

As many pet rat owners know, rats are highly social animals, says study coauthor Inbal Ben-Ami Bartal, a psychologist at the University of Chicago. Bartal and colleagues wanted to see whether rats would take action to ease the suffering of a cage mate. The team put one rat inside a clear cage that could be sprung from the outside, and left another rat to roam free outside the cage for an hour at a time.

Initially, the free rat would circle the cage, digging and biting at it. After about seven days of encountering its trapped friend, the roaming rat learned how to open the cage and liberate the trapped rat. “It’s very obvious that it is intentional,” Bartal says. “They walk right up to the door and open the door.” The liberation is followed by a frenzy of excited running.

The rats would selectively take action when another rat was in distress: Empty cages didn’t inspire rats to learn how to open the door nearly as well as those who were motivated to rescue a trapped rat. By the end of the experiment, only five of 40 rats learned to open an empty cage, while 23 of 30 rats learned to open the cage to free an occupant. (And trapped stuffed animals fared no better than empty cages.)

“If I open the door, that rat’s distress goes away and my distress goes away,” psychologist Matthew Campbell of Yerkes National Primate Research Center at Emory University in Atlanta, who studies empathy in chimpanzees. “They are affected by what the other is experiencing, and that alone is remarkable.”

To push the limits of the rats’ goodwill, Bartal and her team pitted a trapped rat against trapped chocolate, forcing a rat to choose which one to release. “These rats adore their chocolate,” she says. The results astonished Bartal: The rats were equally likely to free a rat in distress as they were to free the sweets. To a rat, a fellow rodent’s freedom was just as sweet as five chocolate chips.

And the niceness doesn’t stop there: “The most shocking thing is they left some of the chocolate for the other rat,” Bartal says. The hero rat left a chocolate chip or two for its newly free associate in more than half of the trials. On purpose. “It’s not like they missed a chocolate,” Bartal says. “They actually carried it out of the restrainer sometimes but did not eat it.”

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Comments 15

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Wow...bummer for religious fanatics. Morals that were not taught by the bible. That should put a dent on their God theory.

George Martinez

Dec. 9, 2011 at 3:35pm
"After about seven days of encountering its trapped friend..."

Did they really keep a rat stuffed in a bottle for seven days? What meanies.

jose willow

Dec. 12, 2011 at 9:58am
The rat's behavior is not necessarily altruistic. Perhaps trapped-rat is important to moral-rat in some selfish, practical way. Even with humans every "altruistic" activity ultimately has some reward, even if it only that fuzzy feeling. It is doubtful that rats get a sense of do-goodism from helping other rats. On their level it is almost certainly some selfish, practical motive connected with survival.

r crowley

Dec. 12, 2011 at 9:58am
How wonderful. A reminder of the Good Samaritan Story.

Wayne Johnson

Dec. 12, 2011 at 9:58am
Has anyone read British author Terry Pratchett's novel, The Amazing Maurice and His Educated Rodents? Obviously, the renowned fantasy author knew all this years ago! My students, who have read the book, will definitely enjoy learning about this research.

boxplayer

Dec. 12, 2011 at 9:58am
@George Martinez:
Can't speak for the "fanatics", but Jesus spoke to this some 2000 years ago:
"You have heard that it was said, 'You shall love your neighbor and hate your enemy.' But I say to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you, that you may be sons of your Father in heaven; for He makes His sun rise on the evil and on the good, and sends rain on the just and on the unjust. For if you love those who love you, what reward have you? Do not even the tax collectors do the same? Mt 5:43-46

Tom Brennan

Dec. 12, 2011 at 9:58am
@r crowley

If you say rats saved their own kind because of some selfish reasons, then how would you explain the chocolate they left for the other rat?

Clearly they left some chocolate behind out of good will.
Say if you are a selfish person, would you leave money for others so they can enjoy?

Hugo Ho

Dec. 13, 2011 at 9:41am
After reading this report, I'm wondering if perhaps the flippant Douglas Adams hit upon something when he suggested that humans are only the third most intelligent species on Earth, bettered by dolphins and mice, the most intelligent.

And if mice really are genuinely altruistic (contrary to r crowly above), would that not reinforce Adams' suggestion?

Mark of Alton

Dec. 13, 2011 at 12:11pm
If the rats had to choose between freeing chocolate, or a fellow rat, then how did they leave some chocolate behind? They had to have freed both the chocolate, and the fellow rat. No? Did rats help write this article? I think I smell a

Ken Cartisano

Dec. 19, 2011 at 10:07am
@r crowley,

It seems that your definition of empathetic behavior as "not altruistic because of a selfish desire for feel-goodies" is, at best, a kind of wordplay. It seems much more plausible that the rat, like the person who does something altruistic, does it because it's right, without regard for the secondary effects like satisfaction at doing something right.

Aaaand to claim that every altruistic behavior in humans has some secret selfish motive seems really kind of ridiculous if you actually think about it. How do you know what motivates people who do altruistic things? How could anyone know? And what about people who sacrifice their lives to save others? It seems like a stretch to claim that, in the moments before they die, they get sufficient feel-goodies to compensate for their upcoming death. Scratch that--it seems ridiculous.

If anything, I think that "all good behavior is secretly selfish" thing says more about the sort of person who advances such ideas, than about altruism in general.

s attanaphone

Jan. 23, 2012 at 11:05am
We are all rats now!

Gary Brown

Jan. 23, 2012 at 11:05am
Rats living in captivity, view captivity differently than rats living in the wild.

I lived in a rural community of Iowa where numerous farm rats chewed their way into a live containment mouse trap to kill/eat defenseless mice. Perhaps the incarcerated occupants, being mice, had instilled a cannibalistic prejudice in the empathetic hearts of the rats? This model demonstrates that the rats took advantage of the mice, which had neither exit nor sheltered safe harbor for retreat.

In a trapped but controlled lab environment, a rat will ‘know’ that they will have future alternatives. However, a rat in the wild, confronted with survival, shall always take the path that provides the best means for its own welfare. This scenario is also held to be true in humanity.

Gary Brown

Jan. 23, 2012 at 11:05am
What goes on inside the mind of a rat is unknowable, but then you can say that about another person. Altruistic or not, rats who free trapped rats are helping the species survive. I suspect rats tend to live close to where they were born so any neighbors they free are probably related to them. Helping to spread their altruistic genes. An interesting question is of the ones who don't free the trapped rat, is it because they couldn't figure out how to work the mechanism or did they just not care. Are there sociopathic rats? Is the percentage of sociopathic rats in the rat population higher or lower than in human populations?

greg451

Jan. 23, 2012 at 11:05am
"Wow...bummer for religious fanatics. Morals that were not taught by the bible. That should put a dent on their God theory."

I suppose it would if the 'God theory' suggested that morals are only taught by the bible .

Nate Van T

Jan. 23, 2012 at 11:05am
... in other news, Ethical Humans Refuse to Release Rat Researchers from Locked Research Lab.

groobiecat

Jan. 31, 2012 at 9:14am

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