Scientists discovered that jellyfish can learn from experience, even though they don't have a brain. They trained tiny Caribbean box jellyfish to spot and dodge obstacles in a tank. At first, the jellyfish bumped into the walls often. But after just 7.5 minutes, they learned to stay farther away and avoid crashing. The jellyfish learned by connecting what they saw with what they felt when they hit something. This discovery is surprising because scientists thought you needed a complex brain to learn this way. It shows that even simple animals with basic nervous systems can learn quickly, suggesting learning might be much older in evolution than previously thought.