At least 40 reported incidents of boats encountering aggressive orcas off the coast of Spain and Portugal are leading researchers to believe that the animals could be deliberately targeting sail boats.

It was in July when a sailing vessel radioed to be towed back to shore after reporting how a group of orcas repeatedly hit their boat and damaged its rudder. This was followed by another similar incident in August, after a French vessel sought assistance from the coast guard saying they were under attack by killer whales. That same day, another report came in from a Spanish naval yacht that even had a video showing its crew trying to outrun the orcas who were pursuing the vessel. September brought in a report about a Scottish man who had a killer whale bashing and chewing on his sailboat for 45 minutes, causing the wheel to spin out of his hands as his boat spun around.

Marine biologists from the Spanish conservation organisation CIRCE may have an explanation for these attacks. The relationship of humans in relation to orcas seems to have been on a knife-edge ever since fishing vessels have become competitors in their hunting grounds.

Orcas are known to pursue their favourite prey, bluefin tuna, The fish migrate through the hundreds of miles along the coast of Portugal and Spain to breed in the warmer Mediterranean waters.

According to an article from the BBC, about 60 killer whales are documented to be inhabiting these waters. Three of these were identified as the "rogue" individuals and were found to be marauding juveniles. Scientists have come to one particular conclusion drawing from years of observations. The three teenage orcas were said to have been playing and celebrating after a hunt.

However, scientists also found out that one of the juveniles acquired a severe injury on its head which appeared to have been caused by the propeller of a boat. This revelation caused a public stir as headlines started to peg these attacks as orchestrated revenge attacks,

CIRCE marine biologists are still not buying into the idea of revenge attacks. Being known to be intelligent and highly social creatures, they are still trying to work out a solid and founded explanation for their sudden bizarre behaviour.

Killer whales display head butting and other playful gestures in the wild
Killer whales display head butting and other playful gestures in the wild Vancouver Aquarium and NOAA