Killer whale pods have been attacking boats in Spain and Portugal since July (Credit: Spanish Ministry of Transport, Mobility, and Urban Agenda)

Killer whales, or orcas, are the largest members of the oceanic dolphin family. While the intelligent mammals, which hunt in large pods, are known for their orchestrated attacks on unsuspecting marine animals, they have never posed a threat to humans. However, since late July, the normally social animals have been intentionally attacking sailboats off the coasts of Spain and Portugal. The unusual hostility is puzzling scientists worldwide.

The strange behavior first surfaced on the afternoon of July 29, 2020, when Victoria Morris noticed nine orcas circling the 46-foot boat she was crewing near the shores of the Strait of Gibraltar, between Morocco and Spain. The 23-year-old biology graduate was initially delighted to see the friendly mammals, with whom she had numerous encounters while teaching sailing in New Zealand. However, that changed when they began attacking the boat's hull repeatedly for almost an hour. "The noise was terrifying. They were ramming the keel, there was this horrible echo, I thought they could capsize the boat. And this deafening noise as they communicated, whistling to each other. It was so loud that we had to shout," she said.

The continuous attacks not only caused the boat to rotate 180 degrees but also broke its automatic rudder, leaving the four-person-crew stranded in the Strait of Gibraltar shipping lane. By the time the coast guard arrived to rescue them, the orcas had left. Rocío Espada, a marine biologist at the University of Seville who has been working with orcas for many years, says, "For killer whales to take out a piece of a fiberglass rudder is crazy. I've seen these orcas grow from babies, I know their life stories, I've never seen or heard of attacks."

Spanish officials have banned small boats from sailing in the area where the orca attacks are occurring (Credit: Spanish Ministry of Transport, Mobility, and Urban Agenda)

As it turned out, Morris and her crew were not the first to encounter the aggressive mammals. Six days earlier, on July 23, 2020, Alfonso Gomez-Jordana Martin had a similar encounter with four orcas that rammed into his boat for over 50 minutes. "Once we were stopped, they came in faster: 10-15 knots, from a distance of about 25m," he says. "The impact tipped the boat sideways."

The previous night at 11.00 pm, a few killer whales brought Beverly Harris and Kevin Large's 50-foot yacht to a halt and spun it around several times for about 20 minutes. "I had this weird sensation," Harris says, "like they were trying to lift the boat." Earlier that same night, the mammals hit Nick Giles' 34-foot yacht with such force that it disabled the steering. They then proceeded to push the vessel for 15 minutes before finally abandoning it.

Since then, over 30 more similar incidents have been reported. On September 23, 2020, Spain's transport ministry banned yachts of less than 50 feet in length from sailing in the approximately 60-mile stretch of the Atlantic coastline between Ferrol and the Estaca de Bares Cape, where the attacks have been occurring. "The measure is intended to prevent new encounters with the orcas which have, over recent weeks, been responsible for various incidents in Galicia's coastal area, mainly involving sailing vessels," the officials said in a statement.

Researchers across the world are trying to explain the orcas' aggressive behavior (Credit: Spanish Ministry of Transport, Mobility, and Urban Agenda)

The orcas' unusual behavior has researchers scrambling to find answers. Some believe that the hostility could be a result of the overfishing of the bluefish tuna — the mammal's primary food source — which has left the area's small population of about 50 killer whales starving and unable to feed their calves. "I saw them [orcas] look at boats carrying fish. I think they know that humans are somehow related to food shortages," says Ken Balcomb, senior scientist at the Center for Whale Research in Washington, USA. Others believe the sudden increase in boat traffic and fishing activities, after months of absence due to COVID-19 restrictions, could also be contributing to the agitation.

However, Alfredo López, a biology professor at the Coordinator for the Study of Marine Mammals (CEMMA), in Galicia, Spain, thinks the attacks are defensive measures the orcas adopted to protect themselves against boat injuries. The researcher came to this conclusion after looking at the footage of a few incidents and noticing that two of the young killer whales involved had serious injuries. The scientist is not sure if the orcas were hurt during or before the recent boat encounters. "It's not revenge. They're just acting out as a precautionary measure." Lopez told Spanish daily newspaper, El Pais. "Our interpretation is that they don't have the slightest intention of attacking people." Hopefully, the experts will be able to find a way to restore the harmony between the animals and the humans soon.

Resources: The Guardian.com, ecowatch.com, Newsweek.com.