Scientists at the Yerkes National Primate Research Center at Emory University say they have conducted an experiment on groups of prairie voles that shows the small rodents have empathy for a familiar face after injury, according to a story on discovery.com.

It has been known for some time that animals like dogs, elephants, and dolphins seem to console an injured relative or member of their group, but this is the first indication of such a behavior in rodents.

The experiment involved isolating one of the prairie voles from the other members in their group with which they were familiar, and administering a series of mild electric shocks that member.  When the member was returned to the other members of the group, they immediately began to lick and groom the fur of their injured companion.

The report continued the rodents nurtured the injured member quicker and for longer periods than they did in normal situations where no injury was involved.  Additionally, they noted that the voles did not exhibit the same consoling behavior to injured voles with which they were unfamiliar.

That experiment led to the scientists blocking the neurotransmitter in the brain for oxytocin, known as the love hormone, in some of the animals.  After blocking the receptor, the voles stopped consoling each other.

Larry Young, study co-author and director of the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory University, said many complex human traits are rooted in fundamental brain processes that are shared among many species, and adds the team’s research could lead to the discovery of the role oxytocin could be playing, and may provide insight into the treatment of autism spectrum disorder.  Young cautioned that much more research will be necessary.

Study co-author Franz de Waal, credited with discovering animal consolation behavior in 1979 for his work with chimpanzees, added the findings shine a new light on the number of animals that feel empathy and how the feeling is separate from complex cognition.

He continues, “Scientists have been reluctant to attribute empathy to animals, often assuming selfish motives.  These explanations have never worked well for consolation behavior, however, which is why this study is so important.”

The results of the study were published in the journal Science.