I think a lot of people are confused about the difference between dolphins and porpoises. While whales, dolphins and porpoises are in the same scientific group, Cetacea, they are not the same. A “whale” is a common name used to describe a large cetacean. It relates to there size, much like the distinction between “boat” and “ship”, and killer whales, melon-headed whales, pilot whales, and false killer whales are all part of the dolphin family, but are called whales because of their size.
Here are some of the key differences, according to dolphin specialists.
Porpoise teeth are shaped like spades, whereas dolphin teeth are like cones, and are more pointed. Porpoise teeth, unlike dolphin teeth, have a sharp, upper edge.
Porpoises are smaller and chubbier than dolphins, and their snouts are blunt. Dolphins (just think back to Flipper) have longer, more pointed (like a beak) snout.