It cannot be objected to the view of several canine species having been anciently domesticated, that these animals are tamed with difficulty: facts have been already given on this head, but I may add that the young of the _Canis primævus_ of India were tamed by Mr. Hodgson,[32] and became as sensible to caresses, and manifested as much intelligence, as any sporting dog of the same age. There is not much difference, as we have already shown and shall immediately further see, in habits between the domestic dogs of the North American Indians and the wolves of that country, or between the Eastern pariah dogs and jackals, or between the dogs which have run wild in various countries and the several natural species of the family. The habit of barking, however, which is almost universal with domesticated {27} dogs, and which does not characterise a single natural species of the family, seems an exception; but this habit is soon lost and soon reacquired. The case of the wild dogs on the island of Juan Fernandez having become dumb has often been quoted, and there is reason to believe[33] that the dumbness ensued in the course of thirty-three years; on the other hand, dogs taken from this island by Ulloa slowly reacquired the habit of barking. The Mackenzie-river dogs, of the _Canis latrans_ type, when brought to England, never learned to bark properly; but one born in the Zoological Gardens[34] "made his voice sound as loudly as any other dog of the same age and size." According to Professor Nillson,[35] a wolf-whelp reared by a bitch barks. I. Geoffroy Saint Hilaire exhibited a jackal which barked with the same tone as any common dog.[36] An interesting account has been given by Mr. G. Clarke[37] of some dogs run wild on Juan de Nova, in the Indian Ocean; "they had entirely lost the faculty of barking; they had no inclination for the company of other dogs, nor did they acquire their voice," during a captivity of several months. On the island they "congregate in vast packs, and catch sea-birds with as much address as foxes could display." The feral dogs of La Plata have not become dumb; they are of large size, hunt single or in packs, and burrow holes for their young.[38] In these habits the feral dogs of La Plata resemble wolves and jackals; both of which hunt either singly or in packs, and burrow holes.[39] These feral dogs have not become uniform in colour on Juan Fernandez, Juan de Nova, or La Plata.[40] In Cuba the feral dogs are described by Poeppig as nearly all mouse-coloured, with short ears and light-blue eyes. {28} In St. Domingo, Col. Ham. Smith says[41] that the feral dogs are very large, like greyhounds, of a uniform pale blue-ash, with small ears, and large light-brown eyes. Even the wild Dingo, though so anciently naturalised in Australia, "varies considerably in colour," as I am informed by Mr. P. P. King: a half-bred Dingo reared in England[42] showed signs of wishing to burrow.