Killer whales, scientifically known as Orcinus orca, are among the most recognizable marine animals, famous for their striking black-and-white coloration and powerful presence in the ocean. Despite their common name, which suggests a direct relation to large whale species, many people wonder about their true biological classification. This confusion often leads to the question of whether these marine predators are actually whales or if they are more closely related to dolphins. Unraveling their scientific identity helps clarify their place in the diverse aquatic world.
Their Place in the Whale Family
Killer whales are indeed whales in the broader sense, as they belong to the order Cetacea, which encompasses all whales, dolphins, and porpoises. More specifically, Orcinus orca is classified within the suborder Odontoceti, meaning they are toothed whales. Within this toothed whale suborder, killer whales are the largest members of the oceanic dolphin family, Delphinidae. This family also includes many smaller, more commonly recognized dolphin species, such as bottlenose dolphins. Their substantial size, with males reaching up to 9 meters (30 feet) in length and weighing over 5,400 kilograms (12,000 pounds), often contributes to the misconception that they are a type of large whale.
Distinguishing Whale Types
The order Cetacea is primarily divided into two suborders: Odontoceti (toothed whales) and Mysticeti (baleen whales). This classification is based on fundamental differences in their feeding mechanisms and anatomical features.
Toothed whales, like the killer whale, possess teeth for grasping and consuming prey. They typically have a single blowhole and utilize echolocation, a natural sonar system, to navigate and hunt. Examples include dolphins, porpoises, sperm whales, and beaked whales.
In contrast, baleen whales, such as humpback and blue whales, lack teeth. Instead, they have baleen plates—comb-like structures made of keratin—that hang from their upper jaw. These plates filter large volumes of water to capture small prey like krill and small fish. Baleen whales are also distinguished by having two blowholes.
The Origin of Their Name
The common name “killer whale” stems from historical observations made by ancient mariners. These sailors witnessed Orcinus orca hunting and preying on larger whale species, leading them to call these formidable predators “whale killers.” Over time, this phrase inverted to “killer whales.” This moniker reflects their position as apex predators in the marine food web, known for a diverse diet that can include fish, seals, sea lions, and even other whales. The scientific name Orcinus is thought to derive from Orcus, a Roman god of the underworld, alluding to their powerful predatory nature. While “orca” is increasingly used, “killer whale” remains prevalent, particularly among scientists. The name highlights their hunting prowess rather than their biological classification as dolphins.