A new review paper summarizing the data from hundreds of studies demonstrates that rodents robustly show emotional contagion for the distress of others. Intriguingly, these studies show that the neural structures that allow a rodent to feel distressed when witnessing the distress of others is homologous to the structures involved in human empathy. Interestingly, rodents are also motivated to approach others in distress, and this proximity increases how much they share the distress of others. Rodents also learn to favor behaviors that benefit others. Together, this data provides an new perspective on the evolution of empathy: the sharing of emotions may have evolved in animals for a selfish aim – detecting dangerous situations by witnessing that other animals are scared. Such shared emotions additionally can, under certain circumstances, promote prosocial behavior.