Mistaken Identities: Dolphins vs. Porpoises

In this installment of our Mistaken Identities series, we explore the differences between dolphins and porpoises.

  • Animals

It can be easy to confuse aquatic mammals with one another, especially when they look as similar as dolphins and porpoises. Dolphins and porpoises are both whales and are part of the order Cetacea. This order is broken into two main categories—baleen whales and toothed whales—based on whether the animal has baleen plates or teeth. Both dolphins and porpoises are toothed whales that eat a carnivorous diet, use echolocation, have a singular blowhole and are completely aquatic.

Despite their similarities, there are several differences that set them apart.

Physical Differences

There are several physical characteristics to look for when distinguishing between dolphins and porpoises.

Graphic Illustrating the General Body Differences Between Porpoises and Dolphins
Graphic Illustrating the Differences Between the Dorsal Fin Shapes of Porpoises and Dolphins
Graphic Illustrating the Differences Between the Shapes of Porpoise Teeth and Dolphin Teeth

Other Differences

Size, dorsal fin shape and teeth are some differences that are easy to spot, but they're not the only ways to differentiate between dolphins and porpoises.

Close-up of a Half-Submerged Head of an Atlantic Bottlenose Dolphin Swimming Slightly on Its Side in the Dolphin Discovery Exhibit

Rostrum Shape

Boop! Both dolphins and porpoises have snouts, called rostrums, comprised of lower and upper jaws. However, porpoises' rostrums are rounded and short, while dolphins' rostrums tend to be pronounced and elongated.

Communication Styles

Dolphins are noisy and known for their squeaks and chirps. They communicate with each other by clicking, whistling and making other sounds both in and out of the water. On the other hand, porpoises are quieter—at least to human ears. Some porpoises, like the harbor porpoise, make clicking sounds at a higher frequency than humans can hear.

Social Behavior

Porpoises are more solitary and travel in smaller groups than dolphins. Dolphins are also considered more social and interested in humans than porpoises. In fact, dolphins will approach boats and even surf in the bow wave that forms when boats move. Porpoises will typically avoid surfacing near boats.

Habitat

Porpoises are typically found in the cold water in the northern regions of the Atlantic and Pacific, but they, like dolphins, also live in rivers. Porpoises prefer to live near the coast, while dolphins are more widespread in tropical and temperate climates.

Protecting Dolphins and Porpoises

Even though dolphins and porpoises have differences, their habitats are all threatened by problems like plastic pollution. Dolphins and porpoises often mistake trash, like plastic bags, for food. One way we can help protect these cetaceans is to stop plastic from entering waterways by minimizing our use of single-use plastics. The National Aquarium is also in the process of creating North America's first dolphin sanctuary to provide a new kind of human care for dolphins.

Mistaken Identities More in This Series

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Animals Mistaken Identities: Frogs vs. Toads

Animals Mistaken Identities: Moths vs. Butterflies

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