Deconceptualist, 1 year ago (edited 6 months ago)

No, dolphins and porpoises are separate families. Orcas are with the dolphins. Porpoises are actually closer with other types of whales like belugas and narwhals. At least per the most widely accepted taxonomy.

All of these are classified as cetaceans though (infraoder, above family) and of course have a common ancestor if you go back far enough.