Despite their reputation, rats are surprisingly sociable and actually regularly help each other out with tasks. Researchers at the Universities of Göttingen, Bern and St Andrews have now shown that a rat only has to smell the scent of another rat that is engaged in helpful behavior to increase his or her own helpfulness. This is the first study to show that just the smell of a cooperating individual rat is enough to trigger an altruistic and helpful response in another. The research was published in the Proceedings of the Royal Society B.