First evidence of sleep in snails

(PhysOrg.com) -- Scientists in Canada noticed pond snails spent around 10 percent of their time attached to the side of their tank with their tentacles partly withdrawn, their shells hanging away from their bodies, and with their feet symmetrical and relaxed. The researchers decided to do some experiments to find out if the snails were asleep or just resting, and their results provide the first evidence that gastropods sleep.