The sperm whale is the most famous of the Physeteridae family. It is also the largest of the toothed whales and may dive deeper than any other cetacean. Herman Melville made the sperm whale famous in his classic novel Moby Dick . A similar toothed whale family is the Kogiidae family which includes the pygmy sperm whale and dwarf sperm whale which are significantly smaller than the sperm whale but share characteristics such as the spermaceti organ, the blunt head, and the distinctive narrow lower jaw. Beaked whales are members of the Ziphiidae family.
Beaked whales are the least well-known of all cetaceans.
Some species have never been seen alive and have been studied only when dead animals wash ashore. Beaked whales may be rare or simply elusive but, generally, they live in deep water far from land and are rarely seen. It is believed that there are 20 living species of beaked whales, including the North Pacific bottlenose whale , Shepard's beaked whale, Sowerby's beaked whale, and Stejneger's beaked whale. The family taxonomy has not been agreed upon by the scientific community. Both species lack dorsal fins, have blunt-shaped heads, are gray colored at birth, and whiten as they mature.