Inbal Ben-Ami Bartal of the University of Chicago and her colleagues conducted experiments in which rats liberated their distressed “cagemates” from a trap, even when they didn’t get rewarded for it.

Researchers found that even when the free rats had a supply of chocolate chips within their reach, which they easily could have eaten themselves, the animals still freed their trapped counterparts and shared the treats with them.

The experiments indicated that the free rats recognized the distress of the trapped rats and quickly figured out how to free them rather than just freezing or running around.

It was found that the rats didn’t open containers that were empty or had other objects in them.

The report noted that a greater portion of the female population opened the trapdoor, which they say is consistent with suggestions that females are more empathetic than males.

Details of the study were published in the December 9 issue of the journal Science.

Photo: Science/AAAS