Prairie voles soothe distressed loved ones like humans: study

Like humans, small prairie voles, known for their monogamy, can console loved ones who are feeling distressed, a U.S. study said Thursday.

This was the first time that researchers have shown consolation behavior in rodents.

This discovery, published in the U.S. journal Science, added to a growing body of evidence that detecting the distress of others and acting to relieve that stress are not uniquely human and may be more common in animals than previously thought.

Besides prairie voles, only a few nonhuman species with high levels of sociality and cognition, such as elephants, dolphins and dogs, are known to show signs of empathy.

Prairie voles are particularly social rodents and known for forming lifelong, monogamous bonds and providing bi-parental care of their young, leading Larry Young and colleagues from the Emory University to explore their potential for empathy-motivated behaviors.

The researchers created an experiment where relatives and known individuals of the animals were temporarily isolated from each other, with one exposed to mild shocks.

Upon reunion, the non-stressed prairie voles proceeded to lick the stressed voles sooner and for longer durations, compared to a control scenario where individuals were separated but neither was shocked.

The researchers also found that consoling behavior occurred only between those who were familiar with each other but not strangers, indicating that the behavior is not simply a reaction to aversive cues.

Since "love hormone" oxytocin is associated with empathy in humans, they blocked its receptor in prairie voles in a series of similar consolation experiments and found that this caused the animals to cease consoling each other, but did not alter their self-grooming behavior.

The researchers said the findings have important implications for understanding and treating psychiatric disorders in which detecting and responding to the emotions of others can be disrupted, including autism and schizophrenia.

"Many complex human traits have their roots in fundamental brain processes that are shared among many other species," Young said in a statement.

"We now have the opportunity to explore in detail the neural mechanisms underlying empathetic responses in a laboratory rodent with clear implications for humans." Endit