Killer whales apparently just want to have fun

A small group of killer whales have rammed at least 673 boats, including some that sank, off the coasts of Portugal, Spain and Morocco the past five years.

But more than a dozen experts who have studied the incidents believe the orcas are playing, not trying to cause mayhem. The group, which includes biologists, government officials and marine industry representatives, released a report last Friday theorizing that the whales see the boats’ rudder as a toy.

Based on the observations and reports on the interaction between orcas and boats off Europe’s Iberian Peninsula, the scientists concluded that there was no evidence that the interactions between Iberian killer whales and vessels are aggressive on the whales’ part.

The behavior has more in common with fads seen elsewhere and seems associated with play or socializing, possibly encouraged by a recent increased abundance and availability of prey — reducing the time needed for foraging — and by the reduction in negative interactions with fisheries, according to the 45-page report.

Since 2021, interactions have resulted in the sinking of six vessels: four sailboats and two fishing boats. These interactions appear to be solely attributable to the small Iberian population of killer whales. In many instances, whales ram the rudder, often damaging and even breaking it, rendering the vessel unnavigable and requiring a rescue by local coast guards.

Whales just want to have fun

“This looks like play,” Naomi Rose, a senior scientist at the Animal Welfare Institute who was part of the working group, told The Washington Post. “It’s a very dangerous game they’re playing, obviously. But it’s a game.”

The researchers found that, in most cases, the orcas approaching the vessels were among about 15, mostly juvenile, whales. They typically approach slowly, almost as if to just bump the rudders with their noses and heads. But even young orcas average between 9 and 14 feet long, so the rudders would often get damaged or destroyed when the whales touched them, said Alex Zerbini, who chairs the scientific committee at the International Whaling Commission, a global body focused on whale conservation.

“There’s nothing in the behavior of the animals that suggests that they’re being aggressive,” Zerbini, who is also part of the working group, told the Post. “As they play with the rudder, they don’t understand that they can damage the rudder and that damaging the rudder will affect human beings. It’s more playful than intentional.”

Why do whales ram boats?

According to the report, contacting the rudder might have evolved from “prop watching” — whales placing their head near the propeller wash. Zerbini said it could have started with one curious, young killer whale that became enthralled by the bubbles surrounding a moving ship.

“Maybe that individual touched a rudder and felt that it was something fun to play with,” he said. “And, after playing, it began propagating the behavior among the group until it became as widespread as it is now.”

However, it was also noted that the number of juveniles, which are typically the most curious and exploratory in killer whale populations, increased well before this behavior arose. It was suggested that some level of playful interactions began earlier with young juveniles, although these initial interactions did not result in rudder damage. This playful behavior may have escalated as the animals grew older. It was further noted that these same killer whales have been associated with small-scale fishing vessels for decades in Morocco, without damaging them, according to the report.

It was suggested that perhaps the rudders of the Moroccan vessels are not as interesting to the whales. Killer whales are known to play with other objects or animals in their environment to the point of damaging them (in the southern resident killer whale population of Washington state, which feed on salmon, individuals will “play” with harbor porpoises to the point of killing them, which may be a similar escalation of an initially less harmful interaction), so this behavior seems on that spectrum, the report says.

Scientists also surmised that the behavior may have evolved because the whales, for the first time in a couple of generations, are well-fed, have leisure time and experience reduced negative interactions with fisheries.

What can be done?

According to the report, mariners are using deterrent methods in an effort to stop whales from interacting with their vessels, mostly without success.

The working group proposed several methods for keeping the whales away from boats’ rudders, including the concept of a hukilau, a series of weighted, vertical lines hanging in the water column, used for fishing. Whales won’t swim through the lines in situations where an effort is being made to herd them in a particular direction. The scientists also considered striking metal pipes under the waterline to make a banging noise. They also discussed replacing the typically smooth surface of a rudder with abrasive or bumpy materials. The report suggested testing begin as soon as possible.

“We don’t want to see more boats being sunk and we don’t want to see people in distress,” Zerbini told the Post. “But we also don’t want to see the animals being hurt. And we have to remember that this is their habitat and we’re in the way.”