‘We know more about the rings of Saturn than we know about the narwhal,’ writes Barry Lopez in Arctic Dreams. This ignorance extends to its etymology. Wondering why the animal remains ‘so obscure and uncelebrated’, Lopez believes that the answer lies partly with ‘a regrettable connotation of death in the animal’s name’:
The pallid color of the narwhal’s skin has been likened to that of a drowned human corpse, and it is widely thought that its name came from the Old Norse for “corpse” and “whale,” nár + hvalr. A medieval belief that the narwhal’s flesh was poisonous has been offered in support of this interpretation, as well as the belief that its “horn” was proof at that time against being poisoned.
This is certainly the prevailing etymology. Look up narwhal in most major dictionaries that offer one – American Heritage, Oxford, Merriam-Webster, the Online Etymology Dictionary – and you’ll see the ‘corpse whale’ derivation presented more or less definitively, with a ‘probably’ or two included as insurance.
Lopez shares a different possibility: