Have you ever watched a friend scratching and suddenly felt an itch spring up? Well it turns out that itching might be contagious—at least in mice. Normal mice watching chronically itchy mice in other cages increased their own scratching in as little as 5 seconds, whereas mice placed near nonitchy mice didn’t show any increase in scratching, researchers report in Science. What’s more, it appears sight was the vehicle of contagion, as the effect was maintained in mice who simply watched other mice scratch on video. These results might suggest an evolutionary basis to contagious itching, The Guardian writes.