Yawning can be as contagious between bonobos as it is among people, suggesting that the apes are capable of human-like empathy.

Over five years, scientists compared yawning behaviour in humans and bonobos, a cousin of the chimpanzee said to be the great ape closest to humans.

They found that yawning was equally catching in both species when ‘yawners’ and ‘responders’ were not friends or relatives.

Yawning contagion was already known to be a marker of empathy between individuals who share a close emotional bond. Bonobos are the only animal known to share this trait

The researchers wrote in the journal PeerJ: “Between species, sensitivity to others’ yawns was higher in humans than in bonobos when involving kin and friends but was similar when considering weakly-bonded subjects.”

Human empathy appeared to depend on the quality of relationships shared. In situations where complex social bonds were less in evidence, humans and their ape cousins were on an empathic par.