A kind of whale called also cachalot, from which sperm oil and spermaceti are obtained. Sperm whales frequent tropical seas and live in groups or shoals. They have large, square heads, with a single blow-hole near the extremity of the snout. They have no whalebone plates in the mouth, but the lower jaw is furnished with large, conical, curved teeth, and when the mouth is closed the teeth fit into cavities in the upper jaw. They sometimes grow to the length of 80 feet.