Iberian Orca and calf (Photo By Renauddestephanis – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=77951957)

Dear Readers, a while back I wrote a post about the Orcas who live around the Straits of Gibraltar attacking sailing boats, and I thought it might be interesting to revisit the subject in the light of some more recent research. At the time, there were a lot of stories along the lines of ‘orcas taking revenge on rich people with yachts’ following the sight of some scars on a matriarch orca called White Gladis – these were thought to be the result of a boat collision. Alas (because this was a most excellent story), the scars are now thought to be the result of a little ‘tooth-raking’ within the orca pod, which is almost the equivalent of a hug.

However, the theories that remain suggest the complexity of these human/whale interactions. You can watch a fascinating film about the way that this saga has developed here, but the first theory relates to the food that the orcas eat. The Iberian orcas feed more or less exclusively on blue-fin tuna, and they hunt them in a very particular way, by corralling an individual tuna and then ramming it with their snouts. This behaviour seemed to some cetacean experts to be very similar to the way that adult orcas will bring adolescents up to the boats and watch while the youngsters try to ‘ram’ the rudder, and the theory is that the adults are teaching the young whales how to kill the tuna by letting them practice on the rudder.

One expert, however, suspects that it’s more complicated than this. Fishermen used to shoot the orca, because the number of blue fin tuna was going down and the whales were inclined to ‘steal’ them. However, from 2005-2011 the numbers of tuna went down so much that there was a moratorium on hunting them. The tuna recovered, the fishermen were allowed back if they caught the tuna on a line, and the orcas would come along and steal the tuna, but the difference this time was that a whale-watching industry grew up, worth millions of euros. So, the fishermen learned to endure the attention of the orcas, the tourists were delighted, and, after all, no one is going to shoot a whale in full view of a boat full of children.

The side effect was that the orcas became very familiar with boats, and people, and were no longer afraid of them. So, they started to ‘play’ with the rudders, simply because they could. There’s one film of a whale swimming around a boat with a rudder in its mouth, as if to say ‘see what I did!’ And we know that orcas love to play – see this story about them wearing fish on their heads, or this one about them bringing humans gifts. So I can fully believe that the whales are just being curious and mischievous.

Of course, we can’t rule out other possible explanations – the Strait of Gibraltar is one of the busiest in the world, and the noisiest, and we know that underwater noise can cause whales to strand, and probably to show other behavioural changes. Persistent chemicals also accumulate in orcas, as they are top predators, and this too can cause neurological damage. So, the Iberian orcas will certainly be suffering from a range of stressors, and the boat ramming may well be the result of a whole combination of factors. However, boat attacks are down in 2024 and 2025 due to two simple pieces of advice given to sailors:

• You’re safe in water less than 50 metres deep
• If you see killer whales approaching, run like mad – they don’t seem to attack moving boats, just ones that are at anchor or moving slowly.

It was heartening that even people who had had their boats attacked by orcas were still full of respect for them, and saw them as an important part of the ocean’s ecosystem, rather than a nuisance. Some described it as the most amazing experience of their lives. This definitely gives me hope.