 Mature males average 16 metres ( 52 ft ) in length but some may reach 20 @.@ 5 metres ( 67 ft ) , with the head representing up to one @-@ third of the animal 's length . <unk> to 2 @,@ 250 metres ( 7 @,@ 382 ft ) , it is the second deepest diving mammal , following only the Cuvier 's beaked whale . The sperm whale 's clicking vocalization , a form of echolocation and communication , may be as loud as 230 decibels ( re 1 µPa at 1 m ) underwater . It has the largest brain of any animal on Earth , more than five times heavier than a human 's . Sperm whales can live for more than 60 years . 
