INTRODUCED SPECIES. Animals and plants brought into a country from a foreign land by the agency of man. In the settlement of North America from the Old World scores of species of plants. mostly noxious weeds, and hundreds of species of animals, largely parasitic or destructive to agriculture, have been intro duced. Among plants. chicory, wild garlic, and the water hyacinth of Florida are examples of the great spread of introduced species. Domes ticated animals may escape from captivity and become noxious. The wild pigs of our Southern States and the Galapagos Islands are examples. Goats have become wild in many places, and have wrought great destruction. Thus the island of Saint Helena, which is now a barren rocky desert, was formerly clad with forests. The change has been brought about in four centuries by goats. Cats that have become wild on islands have in many cases exterminated species of birds there. Rats and mice. in some eases previously imported from Asia. have been introduced into this country from Europe, and have spread everywhere, exterminating native species and conquering one another.
The European rabbit was introduced into Aus tralia in 1864 for sporting purposes. By 1879, legislatures were enacting laws for its destruc tion; and recently an important industry has arisen in rabbit-skins and canned rabbit-meat. The setting free of Belgian hares in this country is attended with dangers. (Sec RABBIT.) The mungoos of India was introduced into Jamaica in 1872 to rid the island•of rats, whose depreda tions caused an annual loss of $500,000. In 1882
the mungoos had caused such a diminution in the rats that the annual loss from rats was reckoned at about one-half the former amount; but the mungoos multiplied, domestic animals and barnyard fowls were destroyed by it in vast numbers; next native vertebrates fell a prey, also bananas and other fruits. About 1890 the mun goos became recognized as the worst pest of the island, and as doing vastly more harm than good. Of late veers, however, the depredations of the animal have begun to diminish. (See Mux coos.) Other examples of imported animals which have wrought untold damage might be cited at great length. The English sparrow, the cabbage butterfly, the Hessian fly, the gypsy moth (in Massachusetts) are familiar examples elsewhere described in detail. The reason why introduced animals thrive to so extraordinary degree is because they are removed from their natural enemies, and those that might keep them down have not learned to do so. Usually, in time, enemies are acquired, as they have been by the English sparrow, and thus the balance in nature is restored. Consult: Palmer, "The Danger of Introducing Noxious Animals and Birds," in Year Book of Department of ture (Washington, 1898). Sec ACCLIMATIZA