 The sperm whale is one of the species originally described by Linnaeus in 1758 in his eighteenth century work , Systema Naturae . He recognised four species in the genus Physeter . Experts soon realised that just one such species exists , although there has been debate about whether this should be named P. catodon or P. macrocephalus , two of the names used by Linnaeus . Both names are still used , although most recent authors now accept macrocephalus as the valid name , limiting catodon 's status to a lesser synonym . 
