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Whales, Dolphins, PorpoisesWhales, dolphins and porpoises all belong to the same
category of mammals called cetaceans.
Cetaceans use their flippers for steering, balance, and stopping, but not for moving forward. Forward motion is generated by upward and downward movement of the tail, or flukes. Most cetaceans have a fin on their back, called the dorsal fin, which acts as a stabilizer. Flukes and dorsal fins have no bones. They are mostly dense connective tissue, like the cartilage in people. Generally, cetacean's smooth, rubbery skin has no hair.
Toothed whales feed mainly by catching squid and fish using a vast array of teeth. Teeth are generally the same size and shape and grow in "growth rings" that can be used to determine the animal's age. They breathe through a single "blowhole." Toothed whales include sperm whales, orcas ("killer whales"), belugas, narwhals. Dolphins and porpoises are also toothed whales. Baleen whales have no teeth. Instead, hundreds of plates of bony substance called "baleen" hang from their upper jaw. Baleen whales eat by filtering food from the water through the baleen. The color, number and length of the plates aid in identifying the species. They breathe through two blowholes. Baleen whales include blue whales, humpback whales, right whales
and grey whales.
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Smallest: 4 foot harbor porpoise
Cetaceans
are divided into two groups: