Prairie voles take pains to comfort their stressed out pals and relatives, perhaps offering a rare example of empathy in the animal kingdom, according to a new study in Science.
Empathy is well documented in humans, but scientists haven’t had nearly as much luck confirming its existence among animals. It's only been reported among a few species, including elephants, dogs, and dolphins, though not all researchers agree on what qualifies.
Researchers at Emory University looked for evidence of the behavior in the prairie vole because it's a particularly social species. It's one of the rare rodents that generally mate for life, and it also shares parenting responsibilities, collaborates on building nests, and regularly grooms other voles with licks.
"We don't know if what we experience as empathy is the same thing that the prairie voles experience as empathy."
For the study released on Thursday, the researchers separated acquainted voles and subsequently gave one of the pair a mild shock. When they were reunited, the other vole licked their jolted friend or family member sooner and more often than during control experiments that skipped the shocks.
The underlying mechanism for the consoling behavior appears to be oxytocin, a hormone also implicated in vole monogamy and social bonding among humans. When the scientists blocked the neurotransmitter in prairie voles, the comforting licks stopped too, though self grooming didn't.
"I think it's a very nice piece of work that looks at physiological responses to specific environmental and social stimuli," said Adele Seelke, a researcher in the psychology department at UC Davis who studies prairie voles.
But she cautioned that it's difficult to actually know what's really happening inside the animal's brain. "I personally wouldn't call it empathy," she said — empathy is a human concept, which we can certify in our fellow humans by asking how they feel about what happens to others. But we don't have that luxury with species that can't talk. She added, "We don't know if what we experience as empathy is the same thing that the prairie voles experience as empathy."