What is the difference between an orca and a dolphin? The difference between whales, dolphins and porpoises. - Ocean ... Jun 4, 2019 The main difference between them is that baleen whales have baleen and two blow holes while toothed whales have teeth and one blow hole. Dolphins are toothed whales and the largest dolphin is the Orca (generally mistaken for a whale due to its name killer whale). A related family to dolphins are Porpoises.