Species of toothed whale growing to 20.5 m (67 feet) in length, and having the largest brain of any animal. The name comes from the white, waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter. The species feeds on squid and fish, diving as deep as 3 km (9,800 feet). The sperm whale's clicking vocalization is the loudest sound produced by any animal.
