A sperm whale is a large whale with a large head that has a section in it which contains oil. Any of several large, toothed whales of the family Physeteridae, especially Physeter catodon or P. macrocephalus, of tropical and temperate oceans, whose massive head has a cavity containing sperm oil and spermaceti and whose long intestines often contain ambergris. Also called cachalot. a large whale sometimes hunted for its oil and fat. or cachalot Thickset, blunt-snouted toothed whale (Physeter catodon, family Physeteridae) with small, paddlelike flippers and rounded humps on the back. Sperm whales have an enormous head, squarish in profile, and a narrow, underslung lower jaw with large conical teeth that fit into sockets in the toothless upper jaw when the mouth is closed. They are dark blue-gray or brownish. (Herman Melville's Moby-Dick was presumably an albino.) The male grows to 60 ft (18 m). Herds of 15-20 live in temperate and tropical waters worldwide. They commonly dive to 1,200 ft (350 m), feeding primarily on cephalopods. The whales have been hunted for their spermaceti (a waxy substance in the snout, used in ointments and cosmetics) and for ambergris. The pygmy sperm whale (genus Kogia) is a black dolphinlike whale, about 13 ft (4 m) long, of the Northern Hemisphere that lacks commercial value
In the upper part of the head, above the skull, there is a large cavity, or case, filled with oil and spermaceti