These Orcas Are So Different They Might Be New Species

 If you didn’t know there were different types of orcas, I don’t blame you. Until very recently, they were all assumed to be the same. It was in 2008 when the IUCN said the taxonomy of this genus is clearly in need of review and it is likely that Orchinus orca will be split into a number of different species or at the very least subspecies over the next few years.

 The chief scientists at the Orca Conservancy agreed. I think we eventually will probably have at least 10 different species of killer whale, but it wasn’t until 2013 that scientists were able to prove clear genetic differences between various ecoypes. Now, I’ve already talked about ecotypes before, but I’ve never done a deep dive into each and every one. So, let’s get into it.

 I’m KP, a marine biologist who specializes in marine mammals. Ecoypes are broadly defined as a population of species that survives as a distinct group through environmental selection and isolation. Quick content warning. Since prey selection plays a huge role in the evolution and adaptations of ecoypes, there will be clips of predation.

 Here in the northeastern Pacific, we have three recognized killer whale ecotypes. We’ve got the bigs, resident, and offshore. Bigs killer whales are one of the largest ecotypes in the world. Males can get to be 8 m or 27 ft long. They have a pointed dorsal fin, closed saddle patch, and their eye patch usually slants slightly downwards towards the rear.

 Now, these guys strictly feed on marine mammals, mostly harbor seals and minky whales, but sometimes sea lions and calves of other whales. They live in small pods, usually just three to five individuals. And most of these pods are extremely migratory. They also produce quiet and less frequent vocalizations. They go into stealth mode because marine mammals have far more acute hearing than fish do.

Resident killer whales are the most well-known ecoype and the most intensely studied marine mammals in the world. Thanks to their proximity to large metropolitan areas like Seattle and Vancouver, they prey exclusively on fish and shinook salmon in particular. Resident killer whales are slightly smaller than bigs with males averaging a little under 7 and 1/2 m or 24 ft.

 They often have an open saddle patch and a rounded dorsal fin. The males have tall dorsal fins, and I mean tall. They usually have abnormalities like a wavy edge. Their skulls are smaller, slimmer, and lighter than big skulls. More suited for their diet of fish. This ecotype is highly gregarious with much stronger family bonds than the bigs.

 Living in large cohesive groups that can number in the 20s, they are divided into three distinct populations, the southern, northern, and southern Alaska populations. DNA analysis found no evidence of interbreeding between the bigs and the residents, and that they likely diverged around 300,000 years ago.

 They even come from opposite ends of the killer whale family tree. So for now the two have been reclassified as subspecies. Orchinus orca barely newer. No sorry orchinus orca for the residents and orchinus orca rectapinis for the bigs. I didn’t get I didn’t get to name them. Of the three ego types in the North Pacific, the least understood are the offshore orcas.

 As their name suggests, they live offshore over the outer continental shelf, making it a challenge to study them. What we do know is that they extensively eat shark livers. Because shark skin is abrasive like sandpaper, offshore orcas have teeth that are typically worn flat, sometimes down to the gum line. They live in large pods of 100 to 200 individuals and are the smallest Pacific ecotype with a faint saddle patch and often have nicks in their dorsal fin.

Last year, we learned of a potential fourth type in the Pacific that lives even further offshore beyond the continental shelf. This population appears to be hyperaggressive and prey on large mammals like adult sperm whales. I talked about this population in this video right up here. But let’s move to the southern hemisphere where there are five recognized killer whale ecoypes.

 Type A, type B, B2, C, and type D. Type A orcas are the largest ecoype in the world, measuring up to 10 m or 33 feet long. These killer whales live in ice-free circumpolar waters of the southern ocean. They have a classic black and white coloration and a medium-sized eye patch. Like bigs killer whales, type A feed on marine mammals. There appears to be different populations of type A orcas who have developed different hunting strategies.

One of these populations lives off the coast of Patagonia and have learned how to successfully beach themselves in order to catch furs seals, which highlights how intelligent and even innovative orcas are, especially when it comes to feeding techniques. Type B killer whales, also known as pack ice killer whales, have also developed a unique and innovative hunting strategy, one that you’ve probably become pretty familiar with.

 They’re the ones who coordinate to create a large wave that can either wash a seal off the ice flow or break up that ice flow entirely, so the seal has nowhere to go. Pack ice orcas are smaller than the type A, ranging between 6 to 8 m or 20 to 26 ft. They also live further south, closer to continental Antarctica among the loose pack ice, where they prey on wet seals.

 These orcas have a distinct coloration with large oval eye patches, a dorsal cape that sometimes has a white border. The lighter areas are often stained yellow by sea ice algae called datoms. Type B are one of the rarer ecoypes because of their reliance on sea ice. The ecotype is considered the most vulnerable to climate change with their numbers declining by about 5% annually.

Type B2 orcas, also known as small type B or gerlac killer whales, look very similar to the pack ice killer whales with a dorsal cape and yellowish tint to their skin thanks to the datoms. However, they are smaller, as the name suggests, than the pack ice killer whales with slimmer bodies and a shorter dorsal fin.

 Even their eye patch is smaller and narrower. B2s are found around the Antarctic Peninsula, most often in the Gorlac Strait. Their preferred prey is currently unknown, but they’re not believed to prey on marine mammals like the larger type A’s and B’s. Instead, Gerlac killer whales have mostly been observed preying on penguins.

 Type B2s are also more gregarious than the pack ice killer whales, living in large pods up to 75 individuals. Type C orcas, also known as the Ross sea killer whales, are the smallest orca ecotype. Adult males only reach 6 m or 20 ft long. Their most notable feature is their eye patch, which is narrow and distinctly tilted at a 45° angle.

 The Ross Sea killer whales share quite a few genetic similarities with the pack ice killer whales, and it’s believed that they diverged from each other around 150,000 years ago. The Ross sea orcas exclusively eat Antarctic tooth fish. This fish has the highest caloric content of all other fish in the Ross Sea.

 Because they don’t appear to eat anything other than Antarctic toothfish, researchers are obviously concerned that this puts the Ross Sea killer whales in direct competition with commercial fisheries. Antarctic type D kill killer whales. Finally, my personal favorite. Look at them. They just look so strange. They have a very small eye patch that is absent in some individuals.

 Their long, slim, and curved dorsal fin looks a bit like a scimitar. And their large bulbous foreheads are more closely resembling that of pilot whales or beluga whales than other killer whales. And the head is the head is very different around. And when they roll up out of water, they look like pilot whales.

 Yes, pilot whales. This ecoype has only been seen by humans a handful of times because they live in the treacherous waters between latitudes 40 and 60° south. Waters like the Drake Passage. They were first identified in 1955 by photographs of a mass stranding in New Zealand. They weren’t even captured on video until 2014.

 Just a few years ago, a Noah expedition in the Drake Passage was able to find and take small tissue and blubber samples from some individuals. We got the first ever sample of a type D killer whale. Maybe the answer to our questions right here. Mitochondrial sequencing found type D kill killer whales to be distinct from other populations and probably a unique species entirely.

 Unfortunately, the same study also found the type Ds have the lowest genomic diversity and highest level of inbreeding of any mammal species ever documented. There are other populations in the southern hemisphere that aren’t currently recognized as distinct ecotypes, but they probably should be. One is the flat tooththed ecotype found off the coast of South Africa.

 Like the offshore ecotype of the North Pacific, their teeth are worn flat and often to the gum line because they prey on sharks. This ecoype has been made famous by two brothers, Port and Starboard, who have been documented eating the livers of great white sharks. There are also a population of orcas in the waters of New Zealand and Australia.

 Like the flat-tothed and offshore ecotypes, the New Zealand population also presies on sharks and stingrays. We know very little about the Australian orcas, but they appear to be three distinct populations. Now, things get a little tricky when we move to the North Atlantic where the orcas are poorly studied to this day, especially in the middle and western parts of the ocean.

 Right now, there are two officially recognized ecotypes, type one and type two. These ecotypes were first described in a study of museum and stranded specimens and the main basis for their binary classification was based on tooth wear from which ecological differences were inferred. Specimens with worn teeth were classified as type one and were believed to prey on sharks like the offshore and the flat tooththed ecotypes.

 Specimens with unworn teeth or less worn were classified as type two and thought to prey on marine mammals. But as you might have guessed, these ecotypes are now disputed. But you may have not seen coming that it is by the very same researcher who first identified them. During fieldwork, killer whales with worn teeth were not seen preying on sharks.

 Instead, they were seen feeding on herring. However, blower biopsies from about 200 killer whales found that these orcas also occasionally prayed on seals in Icelandic waters. There are also behavioral and social differences in the populations in Norway versus the ones in Iceland, with pods in Norway typically ranging from 2 to 15 individuals, but sometimes in larger groups up to 50 or even 200.

 Unlike most killer whale populations that live in strict matrinal family groups, the Icelandic orcas lack a clear hierarchy and will disperse to interact with unrelated individuals. Then there are the orcas in the eastern Atlantic off the coast of Canada who don’t fit into either the type 1 or the type 2 categories.

 These orcas are seen in small groups of 3 to seven individuals, but it’s also common to see solitary orcas. One famous orca named Old Then with another orca. In fact, he’s usually seen with a pod of Atlantic white-sided dolphins. Unfortunately, there just isn’t enough data to confirm the existence of multiple populations or ecotypes in that area.

 So, for now, the killer whales in Canadian waters are referred to as the Northwest Atlantic and the Eastern Arctic populations. I haven’t even mentioned the gladis orcas, who have become famous for attacking boats and sinking yachts. This is a small population of about 39 individuals who live in the Atlantic off the coast of Spain and Portugal, occasionally venturing into the Mediterranean.

 They also exclusively prey on tuna and don’t appear to interact with the other Atlantic populations at all. So, they don’t fit into the type 1 or type two ecoypes either. I also get a lot of comments asking about the orcas in the Caribbean and the Gulf of Mexico. Like many ecoypes, the ones that have been seen in the Gulf of Mexico are woefully underststudied, but they are generally considered transboundary or visitors because it is outside of their usual range.

 A genetic analysis of one orca in the Gulf of Mexico found that it was actually an Antarctic ecotype was probably really lost. So, why are all these orca ecotypes with clear physical, behavioral, and genetic differences still considered the same species? It’s because we don’t know how to define a species.

 The definition you probably learned in high school is if two animals can breed and produce fertile offspring, then they’re the same species. But there are three major flaws with that definition. One, several animals that are clearly separate species can and do interbreed to produce fertile offspring. All bear species except pandas can interbreed and produce fertile offspring, but it’s ridiculous to argue that polar bears and sloth bears are the same species.

 Two, we can’t study or examine the reproduction of extinct species like dinosaurs. So, we don’t know which extinct species were capable of interbreeding. But the biggest problem is the animals that reproduce asexually. All New Mexico whiptail lizards are female and physically can’t breed with each other. They essentially clone themselves.

 So under the successful reproduction definition for a species, each individual whiptail lineage is a unique species. And that is just as ridiculous as thinking that polar bears and sloth bears are the same species. Other ways to define a species have become available with the advent of DNA analysis and genome sequencing, including karaotypes, DNA, and even using an animal’s ecological niche.

There are around 24 different definitions of a species, and the long-running failure of scientists and biologists to agree on one is referred to as the species problem. This matters because if we treat killer whales as one global species, then they are data deficient with no obvious threat. But if we look at them individually, a much clearer picture comes into focus.

 Some ecoypes like the bigs and the type B2 killer whales are doing great and their populations are healthy and stable, if not growing. Others are struggling for very specific reasons. The pack ice killer whales are in decline because of habitat loss thanks to global warming. The gladis orcas are at a higher risk of ship and vessel strikes because of their dangerous interactions with humans.

 And there is a very real fear that these southern resident killer whales will go extinct within my lifetime because their preferred prey, shinook salmon, is also critically endangered. If you want to learn more about orca ecotypes and perhaps what you can do to help struggling populations, I’ll put a bunch of links and all of my sources down in the descriptions.