《Natural History（7 自然史第7卷）》：

　　The Mexican hog might be rendered a domestic animal like the common kind; he has nearly the same habits and natural inclinations; feeds upon the same aliments, and his flesh, though more dry and lean, is not unpalatable, and may be improved by castration. When killed, not only the parts of generation, if the flesh is intended to be eaten, (as is also done with the wild boar) must be taken instantly away, but also the glands at the opening in the back, and which are common to both male and female, must likewise be removed, for if this operation be deferred for only half an hour, the flesh becomes utterly unfit to be eaten.

　　These animals are extremely numerous in all the warm climates of South America. They go in herds of two or three hundred together, and unite, like hogs, in the defence of each other. They are particularly fierce when their young are attempted to be taken from them. They surround their plunderers, attack them without fear, and frequently make their lives pay the forfeit of their rashness. In their native country they prefer the mountainous parts to the low and level grounds; neither do they seek marshes nor mud, like our hogs, but remain in the forests, where they subsist upon wild fruits, roots, and vegetables; they are an unceasing enemy to all the serpent kinds, with which the uncultivated forests of the New Continent abound: as soon as they perceive a serpent or viper, they seize it with their fore hoofs, skin it in an instant, and devour the flesh.

　　These animals are very prolific; the young ones follow the dam, and do not separate from her till they are full grown. If taken young they are very easily tamed, and soon lose all their natural ferocity, but they never shew any signs of docility, but continue stupid, without attachment, or even seeming to know the hand that feeds them. They do no mischief, and may be permitted to run tame, without apprehending any dangerous consequence. They seldom stray far from home, but return of themselves to the sty: they never quarrel among each other, except when they are fed in the same trough. At such times they have an angry grunt, much stronger and harsher than that of a common hog; but they seldom scream, only when suddenly surprised, or frightened, when they have a shrill manner of blowing like the wild boar. When enraged they draw their breath with great force, and point their bristles upward which more resemble the sharp armour of the hedge-hog than the bristles of the wild boar.

　　The species of the Mexican hog is preserved without alteration, and altogether unmixed with that of the European hog, which has been transported to, and become wild in, the forests of America. These animals meet in the woods, and even herd together, and yet never produce an intermediate breed. It is the same with the Guinea hog, which has greatly multiplied in America, after being brought thither from Africa.

　　However approximate the species of the European hog, the Guinea-hog, and the peccari, may appear, it is, nevertheless, evident, that they are each distinct, and separate from the others since they inhabit the same climate without intermixture. Of the three, the strongest, most robust, and most formidable, is our wild boar. The peccari, though equally fierce, is yet less active, and inferior as to the engines of defence, his tusks being much shorter. This animal dreads the cold, and cannot subsist, without shelter, even in our temperate regions; nor can our wild boar exist in countries which are very cold; therefore it is impossible that either of them could have found a passage from the one continent to the other, over any northern country; and therefore the Mexican hog cannot be considered as an European hog degenerated, or changed, by the climate of America, but as an animal peculiar to the southern regions of that continent.

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