The question of whether whales consume other whales is complex, depending entirely on the species being discussed. Whales belong to the order Cetacea, divided into two distinct groups: the toothed whales (Odontocetes) and the baleen whales (Mysticetes). This fundamental anatomical difference dictates their diet and predatory behavior. Only one species of cetacean, the largest member of the oceanic dolphin family, regularly hunts other whales for food. Most whales, both toothed and baleen, lack the biological tools or behavioral patterns necessary for such large-scale predation.
The Specialized Predator: Killer Whales
The only cetacean that consistently preys on other whales is the Killer Whale (Orcinus orca), which is technically the largest species of dolphin. These apex predators have evolved distinct populations, known as ecotypes, which specialize in different prey. The “transient” or “Bigg’s” ecotype hunts marine mammals, including other whales, while “resident” ecotypes typically focus on fish.
Transient Killer Whales use sophisticated, cooperative hunting strategies to take down prey much larger than themselves. This is inter-species predation, not cannibalism, as the prey belongs to a different species, though both are cetaceans. Their primary targets often include vulnerable gray whale calves, which they separate from the mother by coordinating their movements.
Hunting a large whale requires immense coordination and brute force from the entire pod. Orcas ram large whales with their heads or bodies to subdue them, or use their tails to hit and disorient the prey. In attacks on gray whale calves, the pod works to physically hold the calf underwater or leap onto its blowhole, preventing it from breathing.
They are also known to target larger species, including minke whales, and occasionally even adult humpbacks or sperm whales. Antarctic Type A orcas, for instance, are known for preying on minke whales.
Feeding Habits of Other Toothed Whales
Beyond the Killer Whale, the remainder of the Odontocetes, such as Sperm Whales, Pilot Whales, dolphins, and porpoises, generally focus on smaller, non-mammalian prey. The Sperm Whale, the largest toothed predator, is adapted for deep-sea hunting, with its diet consisting primarily of giant and colossal squid. While they have teeth, these are mainly used for grasping or aggression between males, not for chewing or killing large marine mammals.
These other toothed species lack the specialized social structure and size required for sustained, cooperative hunting of large whales. However, some smaller toothed whales do exhibit aggressive interactions toward other cetaceans, though usually not for food. For example, short-finned pilot whales have been observed displaying aggression toward sperm whales, possibly linked to competition over shared food sources like squid.
Infanticide, the killing of a juvenile of the same species, has also been documented in several dolphin species, including the bottlenose dolphin. This behavior is thought to be driven by reproductive strategy, where a male kills an unrelated calf to cause the female to return to a state where she can mate again. These aggressive encounters are distinct from the regular, predatory hunting of large whales.
The Role of Baleen Whales
The Mysticetes, or baleen whales, are physically incapable of hunting other large marine animals. This group includes the largest animals on Earth, such as the Blue Whale, Humpback, Fin, and Right Whales. Instead of teeth, they possess baleen plates, which are comb-like structures made of keratin that hang from the upper jaw.
These plates function as a sieve, allowing the whale to filter massive volumes of water to capture small prey. Their diet is composed almost entirely of organisms low on the food chain, such as krill, small schooling fish, and zooplankton.
Different species have developed various filter-feeding techniques. Rorqual whales use lunge-feeding to engulf huge mouthfuls of water and prey, while Right whales use skim-feeding, swimming slowly through swarms of plankton with their mouths open.
The specialized anatomy of a baleen whale, including its enormous, distensible throat and finely fringed baleen, is completely unsuited for pursuing and eating large, fast-moving prey. Consequently, baleen whales are only ever the prey, particularly for the Transient Killer Whale ecotype.