In his System Naturae of 1758, Carl Linnaeus named the narwhal Monodon monoceros, “one tooth, one horn”, although its English name is said to derive from an Old Norse word meaning “corpse whale”, perhaps because of its mottled grey colour and from the observation that it sometimes lies upside down and motionless on the surface of the water, prompting early mariners sailing in northern seas to liken it to a drowned human body. The male is identified by its spiralled tooth or tusk (which is formed from a tooth in the upper jaw that can protrude for two or three metres from the upper lip, with a second tooth sometimes growing into a smaller tusk), although females can occasionally develop one. The tusk, let alone the narwhal itself, has inspired legends and myth – the narwhal was known to whalers and other voyagers in northern waters as the sea unicorn – as well as being an object of desire, symbol of authority and a source of medicinal power. Commenting upon how the Danes he met in Greenland related to him that the frame of the Royal throne in Rosenborg Castle in Copenhagen was made from narwhal ivory, George Tyson thought that “There is nothing wrong in that. If polished and carved, it would make a very handsome, and certainly a very uncommon, chair” (Tyson 2002[1874]: 18).