Why do killer whales attack boats near Gibraltar? Scientists finally have an answer

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Orcas ramming and sinking boats in the Strait of Gibraltar may just be juvenile killer whales playing around and following a certain behavior pattern, a marine biologist says.

Since May 2020, researchers have documented nearly 700 incidents of killer whales colliding with boats near the Iberian Peninsula.

This behavior has puzzled sailors and scientists, and many suspect that the killer whales are teaching each other to attack passing boats in the area.

Theories to explain the strange behavior range from food shortages – orcas see the boats as competition for their preferred prey – to the sudden resumption of water sports activities after the pandemic.

Leading marine biologist Alex Zerbini, chairman of the scientific committee of the International Whaling Commission (IWC) and member of a working group of the Spanish and Portuguese governments, now explains that the killer whales’ behavior is most likely a new “cultural tradition” with no apparent purpose.

In other words, the orcas may just be following a new “trend,” scientists now suspect.

“Different populations often have different dietary specialties that have been maintained through cultural transmission, and these ‘ecotypes’ typically exhibit a variety of persistent behavioral traditions related to their different foraging habits,” the marine biologists’ article states.

“Some populations may also develop unusual and transient behavioral fashions and other peculiarities that appear to serve no obvious adaptive purpose.”

Researchers highlight several strange behaviors that have been observed in orcas at different times over the years.

As an example, they cite that since 1987, killer whales in the South Pacific have developed the habit of carrying dead salmon on their heads. It started with younger animals and spread throughout the population for no apparent reason.

The behavior “disappeared soon after,” only to reappear in the summer of 2008 and then disappear again.

In another case of strange behavior that appeared and disappeared over a 20-year period, pairs of juvenile and adult male orcas were documented exhibiting ritualized ramming or butting of their heads.

In recent incidents, most of the killer whales approaching damaged or sunken ships were juveniles, typically approaching slowly, as if gently nudging the oars with their snouts.

“There is nothing in the animals’ behavior that suggests they are aggressive,” said Dr. Zerbini The Washington Post.

“Not all interactions resulted in vascular damage,” the scientists emphasized.

Researchers suspect that this new behavior in orcas may disappear at some point and reappear at a later date.

“When they play with the oar, they don’t understand that they can damage the oar and that damaging the oar will impact people. This is more playful than intentional,” said Dr. Zerbini.

“It is possible that the current fixation of Iberian killer whales on boats, and in particular on their oars, is a short-lived fad and, if it suddenly ceases, could re-emerge at a later date.”