Popularity: Cetaceans (see-tay-shuhns) are very popular animals, particularly dolphins. Whales are probably most popular for their size, and dolphins popular because many people think they are cute since many breeds have a built-in smile. Porpoises are not as popular, but they are becoming more famous as the difference between dolphins and porpoises is being shared more and more.
Fish Or Mammals? Many people strongly believe that cetaceans are fish, while others strongly believe that they are mammals. So who is right? The truth is cetaceans are mammals. They have everything that qualifies them as mammals: they give live birth, breath air, they even have hair! Yes, cetaceans have little bits of hair on their faces. But these hairs are so small that we can’t see or feel them. In fact, the callosities on a right whale’s face are found wherever hair is.
The Size Of Cetaceans: When people say the word “whale” or even “cetacean” they think of enormous whales that are thousands of feet long. Sorry to disappoint some of you, but no cetacean reaches 1,000 feet. The largest of the cetaceans, the sulfur-bottom whale, also called the blue whale, reaches a max of 110 feet long.
Not all cetaceans are giants. Even though the largest can be over 100 feet how big is the smallest? This may surprise you, but the smallest, the Franciscana, reaches a maximum size of 31 inches.
The Diet Of Cetaceans: There are many breeds cetacean that like to eat different things. But almost all cetaceans share the love of eating fish.
Some cetaceans eat other mammals, fish, squid, crustaceans, and even other cetaceans, while some eat only krill and small fish. Different breeds may prefer different foods.
Two Different Kinds Of Cetaceans: There are two different kinds of cetaceans: toothed whales and baleen whales. Toothed whales, as you can guess, have teeth while baleen whales have baleen. So what is baleen and what is it for? Baleen is a lot like hard hair that helps baleen whales to eat. They use it to filter out tiny animals called plankton from the water. we’ve written all about how baleen works in our sulfur-bottom whale post.
There are more toothed whales than there are baleen whales. In fact, there are only ten species of baleen whale and nearly 100 toothed whales. Included in the toothed whale group are the groups oceanic dolphins, river dolphins, porpoises, beaked whales, beluga and narwhal, and sperm whales. Under baleen whales are the groups right whales, gray whales, and rorquals.
Dolphins And Porpoises: Dolphins and porpoises are not the same thing. In the past any dolphin was called a porpoise by your average person, and only people who understood a lot about cetaceans would always refer to them as dolphins. Unfortunately some “porpoise names” still exist. For instance: common dolphins can be called white-bellied porpoises and common porpoises.
Here are some differences between dolphins and porpoises:
porpoise teeth are round and dolphin teeth are triangular and pointed.
Dolphins are generally bigger than porpoises (even though the smallest of all cetaceans is a dolphin).
A porpoise’s head is small compared to the rest of the body, but a dolphin’s head is perfectly sized to the body.
No porpoise has a prominent beak, but most dolphins do.
Other Good Resources On Cetaceans
Whales, Dolphins, and Porpoises by Mark Carwardine has good information on the identification of cetaceans.
Whales by Zoobooks has good information for kids about cetaceans.
Moby Dick by Herman Melville has some good information on whales embedded in it. (just know that Herman Melville believed cetaceans were fish).
The Blue Planet series on DVD produced by BBC has good information on cetaceans