Why Do Humpback Whales Save Other Animals From Orcas?

Orcas are the ocean's ultimate apex predator. Their high intelligence, complex social structures, cooperative hunting strategies, and ability to echolocate allows them to hunt almost anything in the water. Their predatory success is enhanced by a powerful streamlined body that allows them to reach speeds up to 50 kilometers per hour. They can take on great white sharks, sperm whales, and even boats. The only marine mammals known to intentionally confront mammal-eating orcas and successfully chase them away are humpback whales. Over 100 incidents of humpback whales defending seals, dolphins, and other whales have been documented since the 1950s. And it probably happens way more than we realize because these battles usually take place far offshore. But what is it that drives these humpbacks to save other animals? And haven't we seen other animals like pilot whales chase off killer whales? I'm KP, a marine biologist who specializes in marine mammals. The phenomenon where prey species cooperatively attack a predator is known as mobbing behavior, and it's most common in birds. If you've seen a large raptor like an eagle or a hawk, then you've probably also seen smaller birds like crows chasing them, dive bombing them, and harassing them while squawking and making a lot of noise. Crows will even do that harassing behavior to humans. I don't It's crow attack season. All over the city and beyond, the website CrowTracks is recording dozens of attacks. Most of the time, these smaller birds are trying to drive the predator away from their nest, but mobbing also draws attention to the predator, making stealth and ambush attacks nearly impossible. Mobbing behavior is also seen in mammals. Meerkats are known to mob and harass snakes. Bottlenose dolphins often gang up on sharks, and long-finned pilot whales have been seen mobbing killer whales, often at high speed. Like killer whales, pilot whales are a species of oceanic dolphin. They are the second largest dolphin behind killer whales. But pilot whales have a key advantage, numbers. Killer whale pods usually range from just three or four, sometimes up to 20 individuals, whereas pilot whale pods sometimes number in the hundreds. Studies have found that pilot whales are actually attracted to killer whale vocalizations, and when they hear them, pilot whales from different pods will actually band together in even larger numbers to harass the orcas. Many of these interactions resulted in high-speed chases like the one that we see here. Are those the pilot whales? Those orcas look scared out of their minds. Run! Dang, and this boat is moving fast too. They are flying. Get them! But there are a few key differences between what's happening when the pilot whales take on killer whales and what the humpback whales are doing. In order to understand these differences, we need to talk about the Fans of my channel have seen me talk about orca ecotypes before, but for those of you who are new, there are at least 11 distinct orca ecotypes recognized by scientists, and each one specializes in a very specific type of prey. Of these recognized ecotypes, one primarily eats sharks, another appears to prefer penguins, five exclusively eat fish, and the remaining four ecotypes don't eat fish at all and instead hunt other marine mammals like seals, sea lions, and of course other whales. Now this preference in prey is primarily determined by the culture of each ecotype. Ecotypes that live in the same region can have wildly different diets. For example, one ecotype of orca in the Pacific Northwest known as resident killer whales exclusively eat fish and Chinook salmon in particular. Now another ecotype in the same waters, the big killer whales primarily eat marine mammals, including humpback whales, specifically the juveniles and calves. But so what does that have to do with the mobbing behavior of humpback and pilot whales? Well, pilot whales are harassing the ecotypes that only eat fish. These killer whales don't eat marine mammals, so they are not really a threat to the pilot whale, which is why I said humpback whales are the only marine mammals known to intentionally confront the mammal-eating orcas. Studies on the mobbing behavior of humpback whales found that when humpbacks approached killer whales, 93% of the time it was a mammal-eating ecotype and more than 87% of the time the orcas were actively attacking or feeding. This seems particularly maladaptive for the humpbacks because they themselves are attacked by killer whales and calves and juveniles are the main targets. Killer whales mostly don't pose a threat to adult humpback whales, especially when the adults are in groups. Their sheer size and strength means they could easily wound or kill an orca with the slap of their powerful fluke or pectoral fins. These pectoral fins are massive, measuring over five meters long and weighing at one ton each. They're also flexible, maneuverable, and lined with very sharp barnacles. The sharp barnacles lining their flukes and pectoral fins can cause deep wounds that are vulnerable then to infection. Experts believe these adult humpback whales are reacting to the predation vocalizations of killer whales. Unlike the fish-eating orcas who heavily rely on echolocation to find their prey, mammal-eating killer whales produce quieter and less variable echolocation clicks. They also use echolocation 27 times less often than the fish-eating ecotypes and that's because marine mammals like seals, sea lions, and whales have far more acute sense of hearing, which I talk about in this video right up here. Studies suggest that bigs are trying to be stealthy and don't want to alert their prey so they don't rely on echolocation and instead are more passive listeners. And when the mammal-eating killer whales attack, they suddenly communicate to each other with loud vocalizations. The the art of surprise is over and they can now communicate. This increase in noise appears to alert nearby humpback whales who rush in to defend the targeted prey, possibly thinking it could be a juvenile humpback or even a calf in danger. These battles come at an enormous cost to the humpbacks. They sometimes travel several kilometers just to reach the battlefield and the fighting is vicious and intense, often lasting more than an hour, sometimes up to seven hours. That is an enormous amount of energy they're burning, not to mention they're risking life-threatening injuries. These adult humpbacks are coming to the rescue before they even know what species is being threatened, meaning they don't know whether or not the victim is a humpback whale until after they've joined the battle. That's where the mystery deepens because the humpback whales stay and fight the killer whales regardless of the species under attack. This study on the behavior found that of 115 documented interactions between humpbacks and killer whales, only 11% of the time were the orcas attacking juvenile humpbacks. The other 89% of the time the orcas were targeting different species like seals, sea lions, or gray whales. In some cases, humpbacks were even observed putting seals on their bellies to keep them safe from the killer whales. But why are humpback whales putting their own lives on the line for a seal? It makes sense for them to spend enormous amounts of energy defending their own calves and juveniles of their own species, but there was no apparent benefit to humpbacks continuing to interfere when other species were being attacked. This is something that is rarely seen anywhere else in the animal kingdom. One hypothesis being raised is altruism, which is an unselfish behavior by an animal that may be to its disadvantage but that benefits others. The study that I've referenced a few times today defined altruism as a behavior that increases the recipient's fitness at the cost of the performer's. The paper also found that in the case of humpback whales defending other species, interspecific altruism, even if unintentional, could not be ruled out. There is a potential pitfall here and it's anthropomorphism, which is the attribution of human traits, emotions, or intentions to non-human entities. This often leads people to misidentify animal behaviors like thinking a wild sea otter wants to play with your dog. They don't. They don't. Trust me on this. A great example is the gladis orcas who are attacking boats off the coast of Spain and Portugal. The consensus among marine biologists, one that I agree with, is that the gladis are playing. Attacking these boats is fun for them. Even though marine biologists have been saying this for years about these gladis orcas, people are still saying orcas are getting revenge for things like overfishing, pollution, or climate change. I think people want it to be revenge because we're angry about the harm we've done to the ocean and so we want the orcas to be angry too. As a researcher for the Dolphin Communication Project told CBC, thinking the orcas are out for vengeance is just an act of projection. It's easy to anthropomorphize animal behavior, especially when it's something moving like seeing a humpback whale come to the defense of something smaller and more vulnerable like seals. It's easy to believe these majestic, highly intelligent animals are acting out of the goodness of their heart or maybe even empathy. And that still very well might be the case. We've seen whales demonstrate what very much appears to be empathy. A famous example is the southern resident killer whale, J35, named Tahlequah, who carried around the remains of a dead calf for days on end, which to me looks like the bargaining stage of grief. But as the Center for Whale Research said, we cannot know what is in Tahlequah's mind or assume her thoughts and emotions. She very well could just be confused and thinking that the calf is still alive. And the same is true for the humpback whales who defend these other species. There's no way for us to know what's in the minds of these animals, and that makes it challenging to prove or say without a doubt that they are behaving out of altruism. At least for now, this behavior is very much up for scientific debate. We suggest that humpbacks providing benefits to other potential prey species, even if unintentional, could be a focus of future research into possible genetic or cultural drivers of intraspecific altruism. Now also up for scientific debate is why pilot whales chase and harass killer whales. Like I said, mobbing behavior isn't an ideal explanation for what is going on because the pilot whales are chasing the fish-eating ecotypes who don't pose a threat to them. Another theory is that the killer whales and pilot whales are competing for food. But this explanation isn't ideal either because this orca ecotype preys on herring while the pilot whales mostly eat squid, meaning their prey doesn't really overlap all that much. So like the phenomenon of altruistic humpback whales defending seals, the behavior of pilot whales also remains a mystery.