Experiment finds empathy in mice when rescuing a trapped mate

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Mice are capable of selflessly rescuing fellow rodents, according to a Japanese experiment that showed empathy and sociality in the species for the first time.

The study results were published in the British scientific journal Scientific Reports on April 9.

The joint study team included Hiroshi Ueno, a lecturer of neurophysiology at the Kawasaki University of Medical Welfare, and researchers from the psychiatry department of the Kawasaki Medical School and the Department of Neuropsychiatry at the Okayama University Graduate School of Medicine.

Spontaneous helpful behavior, even with no clear personal reward, was observed in rats, a larger rodent species, in 2011. But the motivation for the rats’ rescue actions, be it social contact, empathy or other factors, was not known.

The team studied the behavior of mice that could move around freely after they saw a mouse trapped in a transparent tube.

The tip of the tube was cut off to allow the confined mouse to stick out its nose to breathe. The other end of the tube was covered by a paper lid.

The 14 other mice were placed in a cage containing the tube and gnawed at the paper lid until their mate could break free. An empty tube with a paper lid on its end was left untouched in the same cage.

The mice exhibited this helpful behavior even for trapped mice that had been raised separately from their rescuers.

In another experiment, mice were rescued from the tube placed on wet bedding in the cage.

The mice also saved anesthetized mice in a tube, showing that their actions were not triggered by cries for help.

Ueno said the results could later be applied in the field of neuroscience.

“The study results will become a great force to pursue basic research in unraveling the cause of diseases that drain empathy and sociality from people,” Ueno said.

The researchers will conduct further tests using anti-anxiety drugs and hormones on the mice to see if their rescue behavior changes.

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