What’s the difference between a Porpoise and a Dolphin?
By Tom O’Brien
People use the terms dolphins, porpoises, and whales to describe marine mammals belonging to the order Cetacea (from the Greek work ketos, “large sea creature”), and often use them interchangeably. The orca, or killer whale, for example, is actually the largest member of the dolphin family.
Dolphins are by far more prevalent than porpoises. Most scientists agree that there are 32 dolphin species (plus five closely related species of river dolphin) and only six porpoise species.
Dolphins are also more talkative than porpoises. Dolphins make whistling sounds through their blowholes to communicate with one another underwater. Scientists are pretty sure that porpoises do not do this, and some think this may be due to structural differences in the porpoise’s blowhole.
Dolphins and porpoises have many similarities, one of which is their extreme intelligence. Both have large, complex brains and a structure in their foreheads, called the melon, with which they generate sonar (sound waves) to navigate their underwater world.
It is likely that more (or fewer) differences between dolphins and
porpoises will be revealed as researchers continue to investigate
these intriguing sentinels of the sea.
- China surveys Yangtze dolphin as extinction looms (straitstimes.com)
- What’s at stake if Northern Gateway pipeline goes through Great Bear Rainforest channels? (vancouverobserver.com)
- Expedition to Count Endangered Chinese Porpoises (livescience.com)
- Patches the dolphin makes rare appearance in OC (ocregister.com)
- Let Santa Claus Help Dolphins and Whales (cyberwhalewarrior.com)
- Dolphins spotted in local river (wcvb.com)