Herman Melville, who died September 28th 1891, joked that narwhals' tusks are used to open letters. He was quite wrong: they are actually used to attract mates. (Narwhals with big tusks are well endowed at the other end too.) From the archive:
赫爾曼 · 梅爾維爾，1891 年 9 月 28 日去世，享年開玩笑說，獨角鯨的長牙用來打開信件。他完全錯了: 他們實際上用來吸引伴侶。(獨角鯨的大獠牙好天生的另一端也。)從存檔:
EVER since Europeans began trading the whorled ivory tusk of the narwhal in the 12th century, people have puzzled over its purpose. Early research was hampered...