Dolphins and porpoises are actually whales. But whales are whales too. And so are narwhals. Sorry for springing that on you without warning, but we’ll get to that later. Let’s get started on our mission to find the differences between dolphins and porpoises first.
Overview of The Dolphin and Porpoise
Dolphins, porpoises, and ‘whales’ are all Cetaceans. I recently learned that Cetacea comes from the Greek word, ketos (huge fish), as well as the Latin word, cetus (whale). So technically, dolphins, whales, and porpoises are whales. Or huge fish if you’re leaning toward the Greek meaning.
Why do we get confused when it comes to dolphins and porpoises? Maybe you think of them as the same thing. Or maybe you know they’re not, but you just can’t see the differences. Regardless, I think the confusion began when we all started misusing the word ‘whale’.
Dolphins: If you count river dolphins, there are 42 species. If you don’t, there are only 38 ocean dolphin species, including orcas, pilot whales, bottlenose dolphins, southern right whale dolphins, spinner dolphins, pygmy killer whales, etc. It’s a mouthful and that’s just 7 of the lot.
All 42 species are divided into 5 larger families. They’re Delphinidae (oceanic dolphin), Platanistidae (Ganges and Indus River dolphin), Iniidae (South American river dolphin), Pontoporiidae (La Plata dolphin), and Lipotidae (Yangtze River dolphin).
Porpoises: There are much fewer porpoise species in the world. The 7 species in the Phocoenidae family include harbor porpoises, vaquitas, Burmeister’s porpoises, spectacled porpoises, Indo-Pacific finless porpoises, narrow-ridged finless porpoises, and Dall’s porpoises.
Similarities
Intelligence: Both dolphins and porpoises are exceptionally intelligent. As a matter of fact, bottlenose dolphins are one of the most intelligent marine animals. They’ve got large complex brains and there’s a structure called a melon in their foreheads. They use it to find their way through the water and hunt for prey with the help of sound waves.
Evolution: Dolphins and porpoises both evolved roughly 50 million years ago. They belong to the toothed whale suborder, Odontoceti, which is the result of land animals that started living in water a long (long!) time ago.
Socialization: When it comes to living in pods and traveling together, there’s no difference between dolphins and porpoises. They’re both very social and they look out for each other in the wild.
Threats: Unfortunately, dolphins and porpoises are twinning when it comes to the threats they face. They’re always at risk of entangling in fishing nets. They also have to dodge boats and ships that zoom through the water at high speeds. Then there’s the horrible impact that noise pollution can have on their health. Noise disrupts the sound waves that they use to navigate and hunt, causes hearing loss, puts them under tremendous stress, and disrupts their breeding. And yes, sadly both are included in a shark’s diet.
Physical Appearance
Dolphins: They’ve got longer noses, their mouths are bigger, their dorsal fins more curved, and their bodies longer and leaner. Both species have teeth but a dolphin’s are sharp and shaped like cones. All 42 species are also much bigger overall. The biggest dolphin is the orca, which weighs as much as 12,000 lbs.
Porpoises: They’ve got rounder heads, smaller mouths, shorter triangular dorsal fins, shorter and portly bodies, and flat teeth shaped like spades. They’re also much smaller overall. The smallest porpoise species, the vaquita, only reaches about 120 lbs. as an adult.
Behavior
Dolphins: Dolphins use their blowholes to chat underwater, which is a little something porpoises can’t do. They also give happy tail slaps and playful bumps when they’re happy, which may be one of the things you didn’t know about dolphins. They’re confident, curious, and so friendly. If you ever find yourself in a jam in the middle of the sea, making friends with a dolphin would be your best bet. Lastly, they steal the show in aquarium performances and movies because of their exceptional minds.
Porpoises: Porpoises can only make clicking sounds and they’re very shy. They start breeding at a younger age, grow faster, and don’t live as long as dolphins.
Habitat
Dolphins: They live in tropical, temperate, and even polar regions. You’ll find them chilling in harbors, gulfs, estuaries, bays, and obviously in open waters. Freshwater dolphins live in rivers and lakes.
Porpoises: Porpoises aren’t as adaptable to different regions as dolphins. They prefer the cold and shallow waters of the Atlantic and Pacific Oceans, and they’ll settle for Mediterranean and Black Sea regions. They’re not adapted for water deeper than 650 feet, so they mostly stick to harbors, estuaries, and gulfs.
Diet
Dolphins: Dolphins help support ocean life by keeping underwater populations in check. Killer whales or orcas eat anything from seals to sharks and rays. Other dolphins eat fish, octopuses, jellyfish, crustaceans, and squid.
Porpoises: Their menu looks pretty much the same but they’re too small to eat seals and sharks. Instead, they are just the right chomping size for these marine predators.
Conservation Status
Dolphins: Hector’s dolphin is the smallest dolphin in the world and one of the most endangered marine species. There’s a chance that the baiji (Yangtze River dolphin) is already extinct and Atlantic humpback dolphins are critically endangered. The Ganges River-, Tucuxi river-, Irrawaddy-, Indian Ocean humpback-, Amazon river-, and Indus River dolphin are all endangered, 4 others vulnerable, and 5 near threatened.
Porpoises: The world’s most elusive animal is a porpoise. Remember the threats about fishing nets I mentioned earlier? Just one of the reasons why the vaquita is going extinct. And it’s not just them because the narrow-ridged finless porpoise is endangered, the Indo-Pacific finless porpoise vulnerable, and the Burmeister’s porpoise near threatened. Don’t worry about the other 3 species because they’re still relatively safe.
