"It's only a game. It isn't revenge [against boats], it isn't climate change, it's just a game and that's it," said Dr Renaud de Stephanis, a scientist based on the south coast of Spain., a marine conservation organisation. He said the orcas, also known as killer whales, appeared to be playing a "game" focused on the boats' rudders - part of the moveable steering apparatus that sits in the water.
"I had the feeling they were training each other," he told us. "There were two calves, and the adult would do it, then watch while the calf did it - like they were transmitting something."Orcas are known to be highly social mammals.
There are ongoing discussions on social media among sailors, with a few proposing methods of defending their boats, including carrying firecrackers to throw into the water if the orcas approach. The idea behind that, explained Monica Gonzalez, was to be as boring as possible. "Keep the rudder still, don't throw anything, don't shout," she said. The orcas should simply get bored and move on.