Ever heard of planarians? These inch-long worms are famous for their remarkable ability to regrow body parts that get cut off. Slice one worm into three parts—head, body, and tail—and each part will regrow the rest of the worm. From one planarian, you get three! How they do it we don't know, but two biologists at Tufts University conducted an experiment to test whether a decapitated planarian could retain its memories, NPR reports.
Knowing that planarians shy away from the light, Michael Levin and Tal Shomrat lured them into lit areas with tasty liver snacks until they got comfortable with light. Then the scientists cut off the planarians' heads. When each body grew back a head, lo and behold, the worms remembered that lit areas were safe and had good food. So how did the bodies regrow heads with that memory? "We have no idea," Levin told National Geographic. "What we do know is that memory can be stored outside the brain—presumably in other body cells," and memories "can get imprinted onto the new brain as it regenerates."