Why are orcas ramming ships? Their newfound leisure time may be to blame, experts say

For the last five years, orcas have been ramming boats sailing near the Iberian Peninsula, causing a handful of them to sink. It’s happened more than 670 times.

The bizarre behavior, which captured worldwide attention, has been shrouded in mystery — until now.

After convening in Madrid in February, a group of experts concluded that the phenomenon is likely the result of a game being played by killer whales who have free time on their hands, or fins.

“The behavior has more in common with fads seen elsewhere and seems associated with play or socializing, perhaps encouraged by the recent increased abundance and availability of prey,” the experts wrote in a recently released International Whaling Commission report.

Bluefin tuna, which orcas prey on, have become more prevalent in the region in recent years, following declines in their populations.

“When bluefin tuna were at low numbers, the whales were preoccupied with finding and capturing sufficient prey,” the experts wrote. “Now, with bluefin recovery, perhaps these whales, especially the juveniles, have more leisure to explore novel behaviors.”

The interactions with boats likely began as “trophy games” initiated by “bold individuals” before spreading to other whales in the region.

“I do think the behavior is likely some type of play on behalf of the whales,” Monika Wieland Shields, the director of the Orca Behavior Institute, who was not affiliated with the report, told McClatchy News.

“They’ve found something novel in their environment that’s engaging to interact with and this behavior has spread through their small population,” Wieland Shields added. “I don’t believe we have evidence that only teenage whales are engaging the behavior however, nor do I suspect it’s fair to say it’s out of ‘boredom’ which implies a much greater understanding of the motivations behind whale behavior than we have.”

It’s also possible, experts said in the report, that a decline in vessel traffic during the COVID-19 pandemic could have played a role in the rammings, though this hypothesis is hard to assess.

The interactions, so far, have remained isolated to a small population of killer whales found off the coast of Spain and Portugal.

The experts further concluded that there is no evidence that the boat interactions are the result of aggression — therefore, they should not be described as attacks.

They recommended that boaters in the region follow a handful of guidelines to minimize these interactions and potential damage. These include: moving away from the whales as soon as they are observed and avoiding any measures that could harm the animals.

They also discussed the possibility of using decoys — such as buoys or dinghies — to distract the animals and keep them from damaging crucial parts of ships.

“There is not at present, or likely to be in the future, a single solution to this issue,” experts wrote. “It is likely that multiple mitigation measures will need to be used in sequence or in tandem to effectively extinguish this behavior or deter the whales from vessels.”

More data should be obtained from these interactions in the future in order to better understand them, researchers concluded.

This story was originally published June 4, 2024 at 9:36 AM with the headline "Why are orcas ramming ships? Their newfound leisure time may be to blame, experts say."