Asian elephants comfort distressed members of their group with reassuring trunk touches and sounds that could be the equivalent of a human soothing a baby, scientists have revealed.
It is the first clear evidence of elephants displaying "consolation" behaviour, previously only demonstrated in great apes, dogs and some crow species.
Scientists spent a year watching a group of 26 captive Asian elephants at a camp in northern Thailand.
The researchers recorded instances when one of the animals was distressed or frightened, for example by a snake rustling in the grass, a passing dog, or an unfriendly elephant.
Typically, when this happened a nearby elephant would walk over and gently touch its upset colleague with its trunk, or put its trunk in the other animal's mouth.
The "trunk in the mouth" gesture is the elephant equivalent of a handshake or hug, according to lead scientist Joshua Plotnik, from Mahidol University in Thailand.
"It's a very vulnerable position to put yourself in, because you could get bitten," said Dr Plotnik, who is chief executive of the non-profit conservation organisation Think Elephants International.
"It may be sending a signal of 'I'm here to help you, not hurt you'.
Supportive elephants also tended to vocalise, often producing a high chirping sound.
"I've never heard that vocalisation when elephants are alone," Dr Plotnik said. "It may be a signal like, 'Shhh, it's OK', the sort of sounds a human adult might make to reassure a baby."
In addition, elephants responded to distress signals of other group members by displaying similar emotional signals - a likely sign of empathy.
Groups of nearby elephants were also more likely to bunch together and make physical contact. Dr Plotnik compared them to humans watching a scary movie moving closer to each other and holding hands.
Professor Frans de Waal, from Emory University in Georgia, US, who took part in the research reported in the online journal PeerJ, said: "With their strong social bonds, it's not surprising that elephants show concern for others.
"This study demonstrates that elephants get distressed when they see others in distress, reaching out to calm them down, not unlike the way chimpanzees or humans embrace someone who is upset."
The key to consolation behaviour is empathy - the ability to put yourself emotionally into another individual's shoes, said Dr Plotnik.
This requires complex thinking, which is why it is so rarely seen in animals, he believes.
In contrast, "reconciliation" behaviour that provides a way to repair broken relationships in social groups has been seen in many more species.
