Orcas are powerful marine mammals and apex predators. They have no natural predators and are bold enough to take on virtually anything else in the sea, including the great white shark.
The killer whale’s predatory nature leads many to ask, “Are orcas sharks?” Certain similarities would suggest that they are. Then again, the killer whale is a mammal rather than a fish. It also has a bony skeleton rather than a cartilaginous one like the shark.
To fully understand the orca killer whale, we first need to understand what type of creature is and how it fits into the ocean ecosystems.
Are Orcas Whales or Sharks?
All whales, dolphins, and pinniped species belong to Cetacea’s taxonomical order.
Baleen whales belong to the Mysticeti suborder, while orca whales belong to the Odontoceti suborder alongside other toothed whales like the beaked and sperm whales.
Within the Odontoceti suborder, there are seven different family groups. The killer whale belongs to the Delphinidae family group alongside all oceanic dolphins, pilot whales, and melon-headed whales.
Although dolphins belong to a separate family and are distinct from whales both genetically and in appearance, they are still “considered whales taxonomically.” However, not all whales are dolphins, only those within the Delphinidae family group, like the Orcinus orca.
Despite that close association, the killer whale is still not truly a whale.
It was never even called a whale, or so it seems. The most popular theory about where the killer whale got its name is that ancient sailors saw it preying on whales and named it the whale killer. Over time, this term got flipped around, turning whale killers into killer whales.
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Even the Latin name for the killer whale, Orcinus orca, has a similar meaning, with orca referring to a type of whale, and Orcinus meaning “of the kingdom of the dead.”
In other words, no one ever called the orca a whale – they called them whale killers, which they still are today.
Just last year, tourists off Bremer Bay on the southwestern coast of Western Australia watched in horror as a pack of 74 orcas took down a 50-foot blue whale in a calculated attack.
The battle for survival lasted three hours as the orca performed a coordinated attack, working together like a pack of wolves.
Such fierce predation is reminiscent of the behavior of another apex predator – the great white shark.
Like sharks, orcas are top predators that dominate our ocean ecosystems. They also have a similar number of teeth to some shark species, similarly shaped dorsal fins, and a comparable status in the food chain.
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Despite those shared characteristics, there is no relation between the orca and the shark. The two species don’t even share a common ancestor. The orca descended from “small deer-like creatures… that ate plants and waded around in prehistoric lagoons over 50 million years ago.”
Sharks, on the other hand, first appeared some 450 million years ago and descended from a “small leaf-shaped fish that had no eyes, fins or bones.”
Why Are Orcas Dolphins?
The orca is the largest member of the Delphinidae family, measuring between 16 and 22 feet long. This is much larger than the other members, the smallest of which is the Maui’s dolphin at just 5.5 feet long.
Despite the size difference, the orca shares many similarities with the other members of the Delphinidae family.
Like dolphins, they’re streamlined and have modified limbs, known as pectoral fins, that propel them through the water.
Both have triangular dorsal fins that are sometimes visible above the surface. They are also monophyodonts, which means they grow only one set of teeth and, should they lose any, they’ll never grow back.
Both orcas and dolphins are carnivorous, feeding on crustaceans, fish, and squid. They also share similar hunting tactics and often work together in coordinated attacks.
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Like the dolphin, orcas adjust their hunting tactics according to the type of prey.
Orcas hunting great white sharks push the shark to the surface before bringing its tail crashing down on the shark’s head.
They then flip the shark onto its back, inducing “tonic immobility.” Once the shark is paralyzed in this way, they target the liver, removing it with almost surgical precision.
Like most dolphin species, orcas communicate using both vocalizations and body language. The clicks, whistles, and pulse calls they emit enable them to communicate with one another, locate food, navigate, and find potential mates.
It’s difficult to believe that the ferocious killer whale is closely related to the cute dolphins we see leaping joyously through the waves, but it’s true.
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It’s not only the orca’s teeth and hunting techniques that resemble the dolphin’s. Like all dolphin species, killer whales are marine mammals that feed their babies for the first few months of their lives.
Female orcas produce milk and nurse their offspring for a year or even more, but rarely for as long as some dolphin species, some of whom have been observed “nursing their offspring for up to ten years after birth.”
What’s the Difference Between a Killer Whale and a Shark?
Unlike orcas and dolphins, which have bony skeletons, a shark consists entirely of cartilage. As a consequence, it belongs to a completely different class. Along with all other cartilaginous fish, sharks belong to the Class Chondrichthyes.
That’s not the only reason that orcas fail to become sharks. Another significant distinction is that orcas are mammals, while sharks are not.
Some shark species give birth to live young, but they don’t provide sustenance to them, nor do they have mammary glands.
The moment a shark pup is born, it must fend for itself and avoid the many threats posed by larger sharks and other top predators.
In the Pacific Northwest, resident killer whales feed predominantly on salmon, whereas transient orcas feed on almost anything that comes their way, including sharks, other whales, sea lions, and even elephant seals.
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Sharks and killer whales may share a similar diet, but they have very different ways of hunting and tools with which to kill.
Like all toothed whales, killer whales are monophyodonts, whereas sharks are polyphyodonts. While the killer whale must survive with one set of teeth its entire lifetime, the shark can lose as many as it likes, growing new ones as necessary.
You’d think a lifetime of fresh, sharp teeth would make species like the great whites stop predators in any ocean ecosystem, but that’s not the case.
Over the past few years, a couple of orca whales named Port and Starboard have scared off the great white population of False Bay near Cape Town, South Africa.
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Up until 2015, False Bay was a hot spot for great white sightings. In 2021, the annual sightings had dropped from 200 to 250 to just five.
Experts initially thought illegal fishing was to blame, but when five great white shark carcasses were discovered nearby in Gansbaai, it was clear that another predator was to blame.
Each of the great white shark carcasses had been ripped open, and both the liver and heart were missing.
This phenomenon isn’t restricted to the southern hemisphere either.
Marine ecologist Salvador Jorgensen of Monterey Bay Aquarium has observed, “When confronted by orcas, white sharks will immediately vacate their preferred hunting ground and will not return for up to a year, even though the orcas are only passing through.”
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Killer whales often orchestrate coordinated attacks, working together like a pack of wolves. This behavior is not so common in sharks and has only been observed in a handful of species, including the tiger shark.
For the most part, sharks are solitary creatures that hunt alone, unlike the more gregarious killer whales.
It might be hard to believe that the fun-loving dolphin family members are one of the world’s top predators, but the rules of taxonomy say otherwise.
Killer whales may behave like great whites from time to time, but they are a completely different species. Not only that, but they also belong to a different taxonomical suborder.
They may be large and predatory, but killer whales are not sharks, nor are they true whales. The Orcinus orca belongs to the same family group as oceanic dolphins, identifying based on their teeth rather than their behavior.
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You couldn’t find two species more different than the blue whale and the orca, but taxonomically, they’re considered to be more similar than the killer whale and its fellow apex predator, the great white.
Killer whales might belong to the dolphin family group, but that doesn’t stop them from dominating our ocean ecosystems or turning other top predators into prey.
Nicky is a British adventurer and animal lover who spends her time exploring the natural world and writing about her experiences. Whether on horseback, underwater, running, hiking or just standing with a fishing rod in hand, she embraces everything her adopted home of South Africa has to offer.