Prairie voles are highly social, but whether they show 'empathy' is unknown. Here, 'demonstrator' prairie voles subjected to a stressor (footshocks) were then placed with 'observer' prairie voles, which groomed the demonstrators. Grooming reduced demonstrators' anxiety-like behaviour and was specific for demonstrators known to the observer, suggesting that it is a social behaviour. Injection of an oxytocin receptor antagonist into the anterior cingulate cortex — a region implicated in empathy in humans — of observers blocked this consolation behaviour.