what's the difference between a dolphin & a porpoise--i alwayws thought one was a fish & one was a mammal ?

Answer 1

Dolphins have cone-shaped teeth, a curved dorsal fin, and beak. Porpoises have spade-shaped teeth, a triangular dorsal fin, and no beak.
I included a link with illustrations.
There is a fish called a dolphin as well, but it's better known as mahi-mahi (see second link).

Answer 2

They're both mammals, but they're from different families. They are, of course, still related, as both are members of the order Cetacea, which also includes whales. Cetaceans are divided into the suborders Mysticeti, which includes baleen whales, and Odontoceti, which includes all toothed whales, dolphins and porpoises.

True dolphins are in the Delphinidae family and have cone-shaped teeth, a beak, and a hook-shaped dorsal fin (generally). Porpoises, on the other hand, are members of the family Phocoenidae. They have spade-shaped teeth, lack a beak, and usually have a triangular dorsal fin.

Neither are fish :D

To sum up:
Cetacea ---> Mysticeti vs. Odontoceti
Odontoceti ---> Delphinidae vs. Phocoenidae

Answer 3

Both are mammals. Both are cetaceans. Differently-shaped noses are one of the technical differences, but the words "dolphin" and "porpoise" can be used interchangeably.

Answer 4

the only difference between them is the shape of the nose. the dolphin is beak shaped while the porpoise is blunt nosed. they are both mammals and related to the whale family.

Answer 5

Both are whales.Porpoise are type of small dolphins and possibly one of the fastest marine mammals,and both are mammals.

Answer 6

both are mammals i think dolphins are larger

Answer 7

Both are mammals and both are cetaceans.