The Sand Shark, Carcharias taurus, is one of the commonest sharks of the Atlantic seaboard. It is of little economic importance, however, as a source of food, leather, or vitamin A (from the liver). Typically sharklike in appearance, it has a prominent snout, five gill-slits on either side behind the eyes, an undershot jaw ringed with several rows of sharp triangular teeth, and a tail with the upper lobe much longer than the lower one. Predominantly light bronze in color, its rough skin, called “shagreen,” has a metallic luster when viewed under water.
A number of species of sharks are dangerous to man; but the sand sharks look more sinister than they really are, for they have never been known to attack human beings. Their relative, the gray nurse of Australia, has a very bad reputation, though, and has contributed its share to the more than two hundred recorded shark attacks from that continent for the years 1840 to 1940. From 1919 to 1949 inclusive, seventy-seven authenticated shark attacks on Australian swimmers and bathers are on record, in addition to thirty-three on professional divers. More than two-thirds of the swimmers and bathers died from the wounds they received. (The gray nurse is only a distant relative of the nurse shark of Florida and the West Indies.)
The largest sand sharks on record measured almost eleven feet it length, but the species does not feed on large prey, voraciously eating many kinds of smaller fishes instead.
Females give birth to living young, a single one at a time, which is especially well-developed at birth. Evidence indicates that the single fetus actively swims about inside the reproductive tract of its mother and that it feeds upon undeveloped eggs that apparently are specially shed into the uterus to provide nourishment for it.
The Mako, Isurus oxyrinchus, is a savage, streamlined shark of the warm Atlantic, renowned for the fighting qualities it shows when hooked. Most game fishermen regard it and its close relative, Isurus glaucus from the Pacific and Indian Oceans, more highly than any other shark. These species take rapidly moving bait, and then swim fast and hard with it, sometimes leaping as high as ten feet or more out of the water in their efforts to escape. They are also known to attack deliberately the man or boat that has them fast. The record Pacific mako was twelve feet long and weighed one thousand pounds. The Atlantic form is said to reach thirteen feet.
Makos are eaters of fish and can capture speedy ones like mackerel. They attack larger fish, too. The Atlantic mako fights with the swordfish, and whole swordfish as well as many pounds of swordfish flesh have been found in its stomach. In the Pacific, makos fight with the black marlin.
The Great White Shark, Carcharodon carcharias, is also called “the man-eater,” a title that it well deserves, since it is undoubtedly the most dangerous of all sharks. Not only does it maim or kill bathers, but without provocation it will sometimes attack small boats. Few living creatures are safe from its huge appetite. Sea lions, seals, sea turtles, sharks, tuna, and a large variety of other fishes have been found