Sperm whale off the Belize Barrier Reef

The sperm whale, ''Physeter macrocephalus'', is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus ''Physeter''. The now outdated synonym ''Physeter catodon'' refers to the same species. It is one of three extant species in the sperm whale superfamily, along with the pygmy sperm whale and dwarf sperm whale.
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