The dolphins kept this up for 40 minutes until the shark lost interest, and the group could swim the 100m back to shore. Another lifeguard, Matt Fleet, on patrol in a lifeboat, saw the dolphins circling the swimmers and slapping their tails on the water to keep them in place. He told the Northern Advocate newspaper that he also had a clear sighting of the shark. “Some of the people later on the beach tried to tell me it was just another dolphin; but I knew what I saw,” he said. Ingrid Visser, of Orca Research, an environmental group, said the dolphins’ behavior was understandable, as they attack sharks to protect themselves and their young, similar incidents had been reported round the world. “They could have sensed the danger to the swimmers, and taken action to protect them,” she said.