The rays are very voracious; their food consists of any sort of fish, mollusc, annelide, or crustacean, that they can catch. So powerful are their muscles and jaws that they are able to crush the strong shell of a crab with the greatest ease. Even in our seas they attain a considerable size. Thomas Willoughby makes mention of a single skate of two hundred pounds' weight, which was sold in the fish market at Cambridge to the cook of St. John's College, and was found sufficient for the dinner of a society, consisting of more than a hundred and twenty persons. Dr. G. Johnston measured a sharp-nosed ray at Berwick, which was seven feet nine inches long and eight feet three inches broad. But our European rays are far from equalling the colossal dimensions of the sea-devil of the Pacific. This terrific monster swims fast, and often appears on the surface of the ocean, where its black unwieldy back looks like a huge stone projecting above the waters. It attains a breadth of twelve or fifteen feet, and Lesson was presented by a fisherman of Borabora with a tail five feet long. The Society Islanders catch the hideous animal with harpoons, and make use of its rough skin as rasps or files in the manufacture of their wooden utensils.
Creatures so voracious and well armed as the rays would have attained a dangerous supremacy in the maritime domains had they equalled most other fishes in fecundity. Fortunately for their neighbours, they seldom produce more than one young at a time, which, as in the sharks, is enclosed in a four-cornered capsule ending in slender points, but not, as in the former, produced into long filaments.
Thus nature has in this case set bounds to the increase of a race which else might have destroyed the balance of marine existence; in most fishes, however, she has been obliged to provide against the danger of extinction by a prodigal abundance of new germs. If the cod did not annually produce more than nine millions of eggs, and the sturgeon more than seven; if the flat-fish, mackerels, and herrings, did not multiply by hundreds of thousands, they could not possibly maintain themselves against the vast number of their enemies. "Not one egg too much," every one will say who considers that of all the myriads of germs which are deposited on the shallow sand-banks and shores to be quickened by the fructifying warmth of the sun, not one in a hundred comes to life, as fishes and molluscs, crabs and radiata, devour the spawn with equal voracity; that a thousand dangers await the young defenceless fry, since everywhere in the oceanic realms no other right is known than that of the stronger; and that, finally, the insatiable rapacity of man is continually extirpating millions on millions of the full-grown fishes. But if very few of this much-persecuted race die a natural death, a life of liberty makes them some amends for their violent end. The tortured cart-horse or the imprisoned nightingale would, if they could reflect, willingly exchange their hard lot and joyless existence for the free life of the independent fish, who, from the greater simplicity of his structure, his want of higher sensibilities, his excellent digestion, and the more equal temperature of the element in which he lives, remains unmolested by many of the diseases to which the warm-blooded and particularly the domestic animals are subject.