; suborder Odontoceti, superfamily Physeteroidea)
A family of whales in which the head is blunt and more or less rectangular in shape, containing a reservoir filled with spermaceti. Functional teeth are present only in the lower jaw. Sperm whales feed on squid, fish, and Crustacea, diving deeply to do so. They are distributed throughout all oceans. There are two genera, and three species, Physeter catodon (sperm whale), and Kogia breviceps and K. simus (pygmy sperm whales).
Subjects: Zoology and Animal Sciences.