by Editor on August 8, 2014

Dolphins & Porpoises: Do You Know The Difference?

Are These Creatures Dolphins, Or Porpoises?

A Dolphin And A Porpoise Are Similar—But Also Different. Here’s How To Tell Them Apart

The names “dolphin” and “porpoise” are often used interchangeably. And no wonder: to human eyes these two sea creatures look and act very much alike. However, there are some major differences in both appearance and behavior. In addition, they belong to two distinct families of Cetaceans—the scientific order that includes dolphins, whales, and porpoises. Within the Cetacean order, the six species of porpoise are part of the Phocoenidae family, while the 32 oceanic dolphin species are Delphinidae.

All porpoises and dolphins are social, highly intelligent mammals that spend their entire lives in the ocean. They all eat fish, navigate and hunt using echolocation, and communicate with a variety of sounds that they make underwater. But most dolphins have long beaks filled with pointed teeth, while porpoises have blunt faces, smaller mouths, and flatter teeth. Most dolphins also sport a curved dorsal fin, while the same fin on a porpoise is triangular. Overall, a dolphin’s body is lean and narrow, while the porpoise body type tends to be more squat.

Dolphins communicate with a wide range of sounds that people can hear, while most porpoise “talk” consists of audible signals too high for the human ear to detect. Some scientists say porpoises use this high-frequency communication to prevent predators such as killer whales from hearing and locating them. But dolphins don’t need to rely on stealth to keep themselves safe: instead they depend on their terrific swimming speed to stay out of harm’s way. They also travel in larger groups than do porpoises; for dolphins, there is safety in numbers.

By the way, the two cetaceans in the photo above are dolphins—you can tell right away by their long snouts and curved dorsal fins.

For kids: If you’d like to learn more about the dolphin’s place in its food web, visit our sister website, What Eats?, to see what eats a dolphin?

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