Dolphins. Who's investigating who?

At the Institute for Marine Mammal Research (Mississippi), scientists have taught dolphins to exchange for fish any debris that gets into the pool. They helped keep the pool clean. Dolphin Kelly used the system for her own purposes. Realizing that for any piece of paper, regardless of its size, she receives the same amount of fish, she began to hide the paper under the rock and tear off small pieces in exchange for fish.

She didn't stop there. One day she caught a seagull flowing into the pool and got a lot of fish for it - the seagull was large. Then Kelly stopped immediately eating all the fish and began to make supplies, which lured gulls. And then I taught this trick to all the other dolphins, and they all started hunting gulls.