Weeee. That's the sound a snail makes when it's riding on the back of a turtle. When they're not riding turtles, those snails produce a little mucus trail as they creep along the ground. Well, according to research just published in the Proceedings of the Royal Society Biological Sciences, snails also ride along on, weeee, pre-existing mucus trails left by other snails. It's like a snail superhighway. Okay, a snail highway. Okay, a snail way. The research involved marine snails, but probably applies to all snails, which may expend a third of all their energy producing mucus. So an obvious benefit is that individual snails can save energy that would otherwise go into cutting fresh trails. Snail experts had thought this was the case, but the new study proves it. And it wasn't easy—the researchers actually measured the thickness of snail trails. A new trail could accommondate a second traveler without additional mucus. But weathered trails got thicker, as snails added a bit of mucus where necessary.