The orca is the largest living member of the dolphin family.
The orca, or killer whale (Orcinus orca), belongs to Delphinidae, the oceanic dolphin family, even though its common name includes “whale.” It is the only living species in the genus Orcinus and is far larger than familiar dolphins such as bottlenose and Risso’s dolphins. Its whale-like size is one reason people often overlook its dolphin classification.
Orcas are found in oceans worldwide, from polar waters to the tropics. They are apex predators with varied diets: some populations specialize in fish, while others hunt seals, rays, sharks, dolphins or even large whales. Many live in stable matrilineal groups called pods, and hunting methods and vocal traditions can be passed between generations.
Pilot whales are another common source of confusion. They are also members of the dolphin family, but they are smaller than orcas. “Largest dolphin” means largest delphinid, not the largest whale overall: blue whales and sperm whales exceed orcas by a wide margin.