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Whales vs. dolphins vs. porpoises

Nov 02, 2009 by Caitlin Kidder

No, I am not describing some epic battle between the species. As I have explained before, many people do not realize that whales, dolphins, and porpoises are part of the same order, Cetacea. Ceteaceans are split between two main groups - Odontoceti (toothed whales) and Mysticeti (baleen whales). Dolphins and porpoises are within the subgroup Odontoceti, and are closely related to one of the most well-known whales, the orca (aka "killer whales", which actually just large dolphins).


The order Odontoceti1

So what are the differences between whales, dolphins, and porpoises? Whales tend to be much larger than dolphins or porpoises, and can have baleen instead of teeth. Dolphins are smaller (with the exception of the orca), and have pointed snouts that are adapted to their different diets, habitats, and movement patterns. Porpoises are very similar to dolphins, but lack the pointed rostrum (snout), streamlined body, and wave-shaped dorsal fin2.

It is likely that all species of cetaceans have been hunted by humans at one point or another in history. In fact, they may be the most in danger in certain places. The Yangtze river dolphin, or Baiji, is the first well-studied cetacean to have gone extinct due to a variety of factors such as pollution, damming of the river, and hunting3. Another example is in Taiji, Japan, where a massive capture and slaughter of dolphins occurs each year4 - a topic which I plan on exploring extensively in following posts.

There is an astounding diversity of cetaceans in our oceans, many of which are threatened directly by human activity like hunting. Just as it is important to maintain biodiversity on land, it is just as important (if not more important) in the sea. We should all be humbled by the dozens of cetaceans who we are inextricably linked to through the web of life.


Cetacea5

1Cetacean Paleobiology - Odontoceti
2Differences: dolphins to porpoises
3Baiji
4Dolphin drive hunting
5Cetacea

Comments:

Ref your website - thediagram showing the diverse cetcean family is too small to be legible. Can you please enlarge it. regards David Clegg

Posted by dave on July 28, 2011 at 04:38 AM EDT #

Ref your website - thediagram showing the diverse cetcean family is too small to be legible. Can you please enlarge it. regards David Clegg

Posted by dave on July 28, 2011 at 04:38 AM EDT #

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