Why Orcas Are Sinking Boats: Scientists Debunk "Revenge" Theory

For the past few years, sailors navigating the Strait of Gibraltar have faced a bizarre and terrifying challenge. Orcas, also known as killer whales, have been ramming boats, snapping off rudders, and in several cases, causing vessels to sink. Early headlines sensationalized this as an “uprising,” suggesting a matriarch whale named White Gladis was leading a coordinated revenge campaign against humanity.

However, a new report from a workshop of international experts tells a very different, albeit still destructive, story. It is not war. It is likely just a game.

The End of the Revenge Narrative

The “revenge” theory gained traction quickly on social media. The narrative suggested that White Gladis had been traumatized by a boat collision or illegal fishing entrapment. Consequently, she was teaching her pod to attack vessels in self-defense. While this makes for a compelling movie plot, marine biologists argue it projects human emotions onto animal behavior.

According to a recent report by the International Whaling Commission (IWC), coupled with data from the Spanish and Portuguese governments, the behavior lacks the aggression associated with actual attacks. If a five-ton orca wanted to destroy a 40-foot fiberglass yacht, it would ram the hull directly and shatter it within moments.

Instead, the whales exhibit surgical precision. They focus almost exclusively on the rudder. Once the rudder is broken or the boat stops moving, the whales typically lose interest and swim away. This indicates they are interacting with a specific moving part rather than trying to kill the “animal” (the boat) or the people on board.

The "Fad" Theory: Cultural Trends in Whales

Biologists now believe the rudder-breaking behavior is a “fad.” Much like humans, cetaceans go through cultural trends. These behaviors start with one influential individual and spread through the group through social learning.

This is not the first time orcas have adopted strange hobbies. The most famous example occurred in 1987 in the Puget Sound area of the Pacific Northwest.

• The Trend: A female orca from the K-pod began wearing a dead salmon on her head like a hat.
• The Spread: Within weeks, orcas from two other pods (J and L pods) began wearing “salmon hats.”
• The End: About six weeks later, the trend vanished as quickly as it started.

The Iberian orcas seem to be in the midst of a similar, though much more expensive, trend. The rudder is a mobile toy. When they push it, the boat spins. It provides a tactile response that the whales find stimulating.

Why Now? The Role of Boredom and Tuna

One of the most surprising factors driving this behavior is the recovery of the Bluefin tuna population.

For years, the orcas in the Strait of Gibraltar struggled to find enough food. They spent nearly all their waking hours hunting. Today, conservation efforts have been successful, and Bluefin tuna are abundant in the region. This leads to a unique problem for apex predators: free time.

• Less Hunting: With food easy to catch, the whales have fewer energy demands and more leisure time.
• Teenage Energy: The primary participants in these boat interactions are juveniles and sub-adults. Like human teenagers with nothing to do, they invent games.
• Playfulness: The interactions are slow and deliberate. Experts note that the whales approach the rudder to investigate and push it, seemingly enjoying the physics of the lever mechanism.

Who Are the Culprits?

The interactions are primarily driven by a specific group of about 15 whales within the Iberian sub-population. This critically endangered group consists of less than 40 individuals total.

While White Gladis is an adult female often seen at the scenes, she may not be the “general” leading the charge. Adult females often supervise juveniles. It is possible she is simply monitoring the younger whales as they play with their “toys,” much like a mother watching children at a playground, even if the playground equipment is a $200,000 yacht.

Current Safety Advice for Sailors

The shift in understanding from “attack” to “play” changes how sailors are advised to react. Early advice suggested stopping the boat immediately to make it “boring.” While this is still a standard recommendation, results are mixed. Some whales lose interest when the rudder stops moving, while others get frustrated and nudge it harder.

Experts strictly warn against using firecrackers, pingers, or weapons to deter the whales.

1. It is illegal: These orcas are critically endangered and protected by strict laws.
2. It adds danger: Pain or panic could turn a playful interaction into an aggressive one, increasing the risk to the crew.
3. It is ineffective: Reports show that orcas often ignore deterrents once they are fixated on the rudder.

The behavior is expected to fade eventually, just like the salmon hats of 1987. Until then, the “Gladis” gang remains a costly nuisance for European sailors, driven not by malice, but by the dangerous curiosity of intelligent giants.

Frequently Asked Questions

Are the orcas attacking humans? No. There have been no reported cases of orcas attacking swimmers or people falling off boats during these interactions. They are interested in the boat’s mechanics, specifically the rudder, not the people on board.

How many boats have been sunk? Since the interactions began around 2020, there have been hundreds of contacts. However, only a small handful of vessels (fewer than 10) have actually sunk. Most incidents result in a broken rudder and a tow back to port.

Will this behavior spread to other oceans? It is unlikely. Orca cultures are distinct. The “salmon hat” fad stayed in the Pacific Northwest, and another fad involving “playing with crab pots” remained local to a different group. This rudder-breaking behavior is currently specific to the Iberian orca sub-population.

What is the “salmon hat” fad? This refers to a documented event in 1987 where a group of orcas in the Puget Sound started carrying dead salmon on their heads. It is the primary evidence scientists use to explain that orcas experience passing cultural fads that have no survival benefit.