[Illustration: Hammer-headed Shark.--(Squalus Zygæna.)]
It is no uncommon thing for the negroes, who are admirable divers, thus to attack and vanquish the dreaded shark, but success can only be achieved by consummate dexterity, and by those who are armed for this express purpose.
Ordinary swimmers are constantly falling a prey to the sharks of warm climates. Thus Sir Brooke Watson, when in the West Indies, as a youth, was swimming at a little distance from a ship, when he saw a shark making towards him. Struck with terror at its approach, he immediately cried out for assistance. A rope was instantly thrown, but, even while the men were in the act of drawing him up the ship's side, the monster darted after him, and at a single snap took off his leg.
Fortunately for the friends of sea-bathing on our shores, the white shark, like his relation, the monstrous Hammer-headed Zygæna, appears but seldom in the colder latitudes, though both have occasionally been found on the British coast.
The northern ocean has got its peculiar sharks, but they are generally either good-natured like the huge basking shark (_S. maximus_), which feeds on sea-weeds and medusæ, or else like the _Picked_ dog-fish (_Galeus acanthius_), of too small a size to be dangerous to man, in spite of the ferocity of their nature.
But the dog-fish and several other species of our seas, such as the Blue Shark (_Carcharias glaucus_), though they do not attempt the fisherman's life, are extremely troublesome and injurious to him, by hovering about his boat and cutting the hooks from the lines in rapid succession. This, indeed, often leads to their own destruction, but when their teeth do not deliver them from their difficulty, the blue sharks, which hover about the Cornish coast during the pilchard season, have a singular method of proceeding, which is, by rolling the body round so as to twine the line about them throughout its whole length; and sometimes this is done in such a complicated manner, that Mr. Yarrell has known a fisherman give up any attempt to unroll it as a hopeless task. To the pilchard drift-net this shark is a still more dangerous enemy, and it is common for it to pass in succession along the whole length of net, cutting out, as with shears, the fish and the net that holds them, and swallowing both together.