Dolphins are known for being highly intelligent.
So intelligent, in fact, that they can communicate with humans even when they have not been trained to do so.

Keller Laros, one of the divers in this video, heard an unusual squeal from the dolphin. He realized the dolphin was in distress; a fishing line was wrapped around its pectoral fin. He described  how he tried to remove the fishing line: “I was trying to unwrap it, I got the fishing hook out of the pectoral fin. … I was worried if I tugged on it, it might hurt him more.”

The amazing part of the video is how cooperative and gentle the dolphin is as the divers help him. Laros was able to get the hook out and snip the fishing line near the dolphin’s mouth.

This video was filmed in Hawaii.