SKIMMING THE SURFACE 



fantastic animals which froHc upon, skim over or leap 

 from the ocean's surface. Composed of ivory, without 

 enamel, it has a central cavity reaching almost to the 

 apex, and the spiral grooves and ridges upon it run in a 

 sinistral (turning from right to left) direction. 



This massive, formidable and in many ways frighten- 

 ing weapon is developed only in the male narwhal, and 

 (with very rare exceptions) only on the left side of its 

 jaw. If it ever happens that a tusk develops on the right 

 side of the jaw it never achieves the size of the huge one 

 on the left of the jaw, but becomes one of a pair of 

 approximately equal length. No case has ever been 

 known of the development of a full-sized right-hand tusk, 

 in association with a smaller left-hand one. In females 

 neither tusk is visible. All other teeth are completely 

 lacking in the male narwhal : all the ivory is used up in 

 its two tusks, with the left-hand one monopolizing by far 

 the greater amount of it. The enormous tusk is a second- 

 ary sexual characteristic of the narwhal — like the antlers 

 of a stag, or the spurs and comb of a cock. 



It has been suggested that the narwhal uses its huge, 

 lop-sided, cumbersome instrument to break ice, and also 

 to transfix its prey — but these suggestions have never 

 been confirmed. For the ice-breaking theory has never 

 been justified by any sight of a narwhal using its huge 

 tusk in such a fashion, while the fact that the creature 

 feeds on cuttle-fishes, small fishes and crustaceans dis- 

 poses of the second suggestion, for the tusk would appear 

 to be valueless as an instrument for attacking its victims 

 or assimilating them. 



Some authorities say that the males do battle with 

 their tusks. William Scoresby and his son (of the same 

 forename), the famous Arctic explorers, described the 

 narwhal as a sportive rather than an aggressive creature, 

 and said that the males were ''extremely playful, fre- 

 quently elevating their horns and crossing them with 

 each other as in fencing". 



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