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teeth only, as in some of the rarer dolphins. Toothed whales have a single blowhole on top of the head, although there are separate nasal passages inside the head, but baleen whales have a double blowhole on top of the head. The largest toothed whale is the huge sperm whale, a deep-diving creature of the open oceans, and the smallest toothed whale is the porpoise, often found close to shore and in large harbors. Baleen Whales Baleen whales range in size from the blue whale at up to 99 feet (30 meters) long to the minke whale at just over 29

CLASSIFICATION OF WHALES AND DOLPHINS Whales and dolphins are collectively known as cetaceans, the word deriving from both Greek and Latin roots, meaning simply “whales.” The whales are divided into two main groups: the toothed whales, or odonto- ceti, and the baleen, or mustached, whales, known as the mysticeti. Toothed whales all have teeth in some form. The teeth may be numerous and almost identical in both jaws, as in the killer whale; present in the lower jaw only, as in the sperm whale; or reduced to one or two

As the blue whale begins a dive and lifts its tail out of the water, the massive tail stock can be seen, showing the powerful muscles the whale uses when swimming.

The upper surface of a humpback whale’s tail fluke, seen just before a dive, is all black with a notched edge, and may measure 13 feet (4 meters) across. This is what provides the power to swim.

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