Dolphins and Porpoises

From: Pieter Arend Folkens (animalbytes@earthlink.net)
Date: Fri Oct 06 2000 - 04:01:52 EDT


Jim:
You asked:
>What is the difference between a dolphin and a porpoise? I thought dolphins
>and some whales were part of the porpoise family. Is that incorrect?

The superfamily delphinoidea contains the families of both dolphins
(Delphinidae) and porpoises (Phocoenidae). There are approximately 47
species of dolphins in the family. I say approximately because the taxonomy
is presently undergoing an important revision. There are six species of
porpoises.

The differences are:
connical-shaped teeth in dolphins; flatter, spade-shaped teeth in porpoises.
If there is a dorsal fin, most dolphin dorsal fin is falcate, that is, it
has a concave curvature to the posterior (trailing) edge. If there is a
dorsal fin on a porpoise, it is much more triangular with a slight curve at
the top.
No porpoise has a prominant beak. Many dolphins have a longish, narrow beak.

There are no dolphins or whales in the porpoise family, but porpoises are,
technically, a dolphin, that is, part of the superfamily delphinoidea.

Killer whales are actually dolphins, but keep in mind that the name whale
does not refer to what they are, rather what they eat. The name comes from
the Basque Ballaena Assasina which translates to whale killer.

Cheers,

Pieter Folkens
A Higher Porpoise DG

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