Since​ summer 2020, orcas near the Strait of Gibraltar and around the Iberian Peninsula have been interfering with boats. Sailing boats are the most common target, and the whales use significant force on them: approaching from the stern, a group of orcas will inspect the boat carefully, swimming alongside it and turning upside down to look at the hull and steering gear, before starting to push the craft around. Sometimes they ram the hull with their heads. They take particular interest in the rudder, which they push with their bodies or grip with their teeth to control the boat. In some cases, the rudder is bent at the stock, split apart or snapped off completely, disabling the craft.

A handful of boats have sunk after these encounters, though this does not seem to be the aim, and the whales tend to depart once the boat stops moving or they have damaged it; perhaps the game is then finished. No one has yet been harmed. It isn’t clear exactly how many whales are involved, but at least eleven individuals of a small population of around forty have been identified as taking part. All the individuals known to have engaged in the behaviour are given the code name ‘Gladis’ by the marine biologists studying the interactions: Gladis Gris, Gladis Negra, Gladis Lamari and so on; juveniles often take the lead but an older female, Gladis Blanca, has participated in the greatest number of incidents. The yachting community now refers to the area as ‘Orca Alley’; a Facebook group set up in 2021, Orca Attack Reports, has attracted 54,000 members, and there are two dedicated apps for reporting sightings or interactions.

The phenomenon periodically returns to wider notice in the media; a spate of incidents early this year prompted another wave of reports and articles. Various explanations have been proposed. Perhaps the behaviour stems from a traumatic incident or encounter with a boat that turned Gladis Blanca and her group against human craft; maybe it’s simply an expression of curiosity or a form of play, its regularity indicating a passing fashion of some kind – orcas are thought to indulge in behavioural fads, which can spread through groups quickly before petering out (the most famous of these involved three pods in Puget Sound that in 1987 spent a few weeks carrying dead salmon around on their heads; in 2005, groups in the same area seemed to experience a less benign craze for tormenting and sometimes killing harbour porpoises, a species they do not eat). The working group that authored the only (and now very widely cited) study of the Iberian orcas’ behaviour also wondered if human pressures on their environment might have prompted the whales to act in this way: the Iberian pods are specialists in hunting the Atlantic bluefin tuna that migrate into the Mediterranean through the strait, a bottleneck where tuna have been fished since prehistoric times. Longline fisheries now operate in the area, and tuna stocks are half what they were forty years ago. The tiny Iberian group requires 1600 tons of tuna per year to meet its requirements for food, and the number of mature adult whales in the population is on a downward trajectory; orca communities are very conservative and tend not to mix with one another, so there is no fresh influx of individuals from outside (some studies even call orcas ‘xenophobic’, so pronounced is their distaste for unrelated communities of their own kind). In 2019 they were put on the IUCN red list as a ‘critically endangered’ subpopulation; the tuna they eat were already on it.

Elsewhere, in response to news coverage, people joke that socialist orcas have joined battle against the super-rich, or are taking revenge for human interference in the oceans; less sympathetic voices feel the ‘orca uprising’ should be put down by force. The orcas no doubt have their reasons for messing about with boats, and speculation about what these might be is mostly simplistic and anthropomorphising. This even goes for the ‘traumatic event’ or ‘ecological disturbance’ hypotheses, which are both crudely mechanistic and presume broadly human-like motives and responses. Orcas are subtle enough for these to be plausible reasons, but there is simply no way of knowing their motives, or what they get out of it. The widespread characterisation of the interactions as ‘attacks’ is heavily loaded, and highly contestable; an open letter from a group of marine biologists published last month asked that people refrain from such interpretations, saying that the idea that orcas were ‘attacking’ vessels was ‘lacking a basis in science or reality’, and could put the whales at risk of ‘punitive responses by mariners or managers’. ‘In the absence of further evidence, people should not assume they understand the animals’ motivations,’ the researchers wrote. ‘Science cannot yet explain why the Iberian orcas are doing this … It is unfounded and potentially harmful to the animals to claim it is revenge for past wrongs or to promote some other melodramatic storyline.’ The boat ramming is as likely, they think, to be socialising and play as anything else. The orcas may simply have found a fun new pastime, and might just get bored of it one day, like the salmon hats or porpoise bullying.

The really remarkable thing about the boat-ramming is that it is happening at all. Not because ambiguous or even apparently aggressive interactions with boats are a completely unknown behaviour in orcas – there are scattered cases going back to the early 1800s – but because they are so rare. Given how many opportunities orcas have for interacting with vessels, and how much certain populations have suffered at the hands of human beings, it is surprising how uncommon it is for them to do anything that could be interpreted as hostile to people (and there is not a single documented case of wild orcas killing a human). The longevity of the Iberian trend and the repeated physical interference with the boats is unique in the historical record. Orcas have been giving us a free pass for millennia.

This hasn’t been because orcas don’t take a close interest in what people do at sea; they do. Orcas understand perfectly well that humans hunt at sea and, like some other species of cetacean, take advantage of it, either by helping fishermen or by stealing from their nets and lines. The Iberian orcas hunt tuna; their technique involves pursuit at speed until the fish are exhausted. This limits the size of the fish they can catch: the biggest tuna are too strong and can outlast the whales’ endurance (about half an hour). But the longlines used by the fisheries snag larger tuna than the orcas can chase down and, since carefully pulling a big fish off a hook is far easier and more profitable than chasing a middling one, the Iberian whales regularly steal from the lines, to the annoyance of the fishermen. This kind of behaviour is common around the world, and bottlenose dolphins, orcas and sperm whales are mostly responsible. Perhaps not coincidentally, these three species are also considered to have the most complex communities of all cetaceans.

Truly co-operative fishing between people and dolphins, typically involving the dolphins herding shoals of fish into the waiting nets of their human partners, has been known in Europe since antiquity: Pliny the Elder devoted an entire section of the Natural History to the phenomenon, which he says could be observed in the lagoons near Narbonne (he also noted the presence of orcas in Iberian seas, recording that they hunted near Cadiz). There are many well-documented examples from all around the world and such cases usually involve forms of inter-species communication between dolphins and humans. Orcas co-operate with people much less than dolphins do, but in the case of the Iberian whales there is circumstantial evidence for at least passive fishing co-operation: as long ago as the mid-18th century, tuna catches were known to be larger when orcas were present.

Fishing is one thing, but only orcas share with humans an interest in hunting whales. There was at least one orca-human co-operative in the days of pre-mechanised whaling. For a hundred years, starting in the 1820s, pods of orcas near Twofold Bay in New South Wales assisted the men of the Eden whaling station in the killing of baleen whales. Orcas in the area were considered to have had sacred fishing relationships with the Indigenous Australian Yuin people since prehistoric times, and the presence of Yuin crew on the whaling vessels is sometimes thought to have been a factor in the development of the relationship. The orcas would locate baleen whales at sea and harass them into a bay, keeping them there while other members of the pod swam – sometimes long distances – to the whaling station. There they would alert the whalers by breaching and lob-tailing (slapping their tail flukes on the water) before guiding the whaling crew to their prey and assisting in the kill, leaping on the backs of stricken whales and trying to cover their blowholes. Their prize was delivered under what became known as ‘the law of the tongue’: the whalers would anchor down the carcass and leave it for a day or so to allow the orcas to prise open the whale’s mouth to eat the tongue and lips (these are typically the only parts of a large whale that orcas consume, even in groups where baleen whales are their only prey; similarly, the South African pods that have recently been observed hunting fully grown great white sharks eat only the liver, which they extract with startling precision).

The Twofold Bay orcas became well known to the whalers and were given individual names; the most notorious of them, a male called Old Tom, was famous for his enthusiasm in the hunt. It was Old Tom who swam to the whaling station to alert the men; it was his habit to fasten his teeth onto the lines holding a harpooned humpback, allowing himself to be dragged along by the desperate whale in the manner of a ‘Nantucket Sleighride’. Old Tom remained faithful to his hunting partners at the whaling station even after the rest of the pod died or disappeared. His skeleton is on display in the Eden Killer Whale Museum; he had ridden so many harpoon lines over the years that the teeth in his lower jaw were worn down and deeply grooved from gripping the ropes.

Orca hunting repertoires are enormously wide and complex. They typically share whatever they catch. Most groups specialise in hunting particular kinds of food – fish, sharks, seals, whales – and do not feed on anything else except under duress. This is not only to do with local conditions: in some areas, coastal fish-eating communities share waters with more pelagic whale-eating communities, but there is no social crossover. Their hunting techniques and preferences seem to be learned and, as with the cultural abilities of humans, this means they can develop and hone new hunting techniques far faster than their prey can adapt. Specialised focus, communicative teamwork and great adaptability means that – also like human beings – orcas can have a hugely disruptive effect on ecosystems when they choose to turn their attention to a new source of food. When a small group of orcas near the coastal kelp forests of the Aleutian Islands started hunting sea otters in the 1990s, they almost entirely eliminated the otters from a large area of the Aleutian coast. The otter’s typical prey was kelp-eating sea urchins. ‘Without otters, the urchins mowed down the kelp, and the forest changed to barrens, a completely different habitat and ecosystem,’ Hal Whitehead and Luke Rendell write in The Cultural Lives of Whales and Dolphins. Orcas may have had impacts on the ocean not dissimilar to the ways early humans affected terrestrial ecosystems, and as far as ecologically destructive overkilling goes, it is even possible that the deep history of the orca as a hunter contains a parallel with the rapacity of human behaviour. The appearance of orcas around ten million years ago correlates with the sudden and mysterious disappearance of more than half the known species of cetaceans, seals and sirenians (dugongs and manatees) from the fossil record. As with the widespread extirpation of terrestrial megafauna from areas colonised by humans during the Pleistocene, one hypothesis is that orcas, as they expanded into new marine ecosystems, hunted many existing sea mammals to extinction. It ‘seems very likely’, Whitehead and Rendell say, that ‘killer whales have eradicated whole species, perhaps many species.’

This shouldn’t be surprising. Orcas are profoundly intelligent beings. Saying non-human animals have ‘culture’ is still somewhat contentious, but most of what is important in orca life is not genetically determined, individually learned or shared by all groups. Anthropologists may puff and blow about calling it culture, but it’s hard to see what other word is more fitting to describe local behavioural traditions, passed on by social learning.

We may understand less about orcas than they do about us. The example of Twofold Bay suggests they are able to understand human desire and intention, at least when it overlaps with theirs. Old Tom knew what the whalers were about – he wanted the same thing, to kill whales for their flesh, and he understood how the entire process worked. Why did he hold the lines? For the sheer joy of the ride, because he revelled in the excitement of the hunt or because he wished to play his part in tiring the whale? Every possibility raises new questions. When the Twofold Bay pods were herding humpbacks into the bay, they must have been thinking about the whaling station and who was there, what they would do if alerted, and how to alert them. Perhaps they had their own pulse-call names for individual boats or whalers, just as the whalers knew and named them. Old Tom was eventually betrayed by a crew led by Captain John Logan, who did not respect the law of the tongue, and tried to haul in a young humpback without allowing the orcas their due. Old Tom struggled against the whalers, losing some teeth in the process: when he was washed up dead sometime later, there were abscesses in his jaw where his teeth had been broken, and he seemed to have died of starvation. Logan, mortified by what he had done, provided the initial funding for the Eden Museum.

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