To which family do oceanic dolphins belong?

Oceanic dolphins belong to the family Delphinidae. The family includes nearly 40 living species of toothed cetaceans found mainly in marine environments, from small coastal dolphins to the much larger orca.

Delphinidae is part of the superfamily Delphinoidea, alongside porpoises and the family Monodontidae, which contains belugas and narwhals. This is why Monodontidae is a tempting but incorrect option: it is a closely related family, not the family of oceanic dolphins.

The family is broader than everyday naming suggests. Orcas, false killer whales, pilot whales, melon-headed whales, and pygmy killer whales all belong to Delphinidae despite having “whale” in their common names. Members typically have streamlined bodies, flippers, a dorsal fin, and teeth adapted for catching fish, squid, or—in the orca’s case—larger marine animals.

Taxonomic studies continue to revise relationships among genera, but Delphinidae remains the canonical family name for oceanic dolphins.