Although it is possible or even probable that domesticated dogs, introduced into any country and bred there for many generations, might acquire some of the characters proper to the aboriginal Canidae of the country, we can hardly thus account for introduced dogs having given rise to two breeds in the same country, resembling two of its aboriginal species, as in the above- given cases of Guiana and of North America. (1/28. These latter remarks afford, I think, a sufficient answer to some criticisms by Mr. Wallace, on the multiple origin of dogs, given in Lyell's 'Principles of Geology' 1872 volume 2 page 295.)
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 primaevus of India were tamed by Mr. Hodgson (1/29. 'Proceedings Zoological Soc.' 1833 page 112. See also on the taming of the common wolf, L. Lloyd 'Scandinavian Adventures' 1854 volume 1 page 460. With respect to the jackal, see Prof. Gervais 'Hist. Nat. Mamm.' tome 2 page 61. With respect to the aguara of Paraguay see Rengger's work.), and became as sensible of 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 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 dogs, forms an exception, as it does not characterise a single natural species of the family, though I am assured that the Canis latrans of North America utters a noise which closely approaches a bark. But this habit is soon lost by dogs when they become feral and is soon reacquired when they are again domesticated. 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 (130. Roulin, in 'Mem. present. par divers Savans' tome 6 page 341.) 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 (1/31. Martin 'History of the Dog' page 14.) "made his voice sound as loudly as any other dog of the same age and size." According to Professor Nillson (1/32. Quoted by L. Lloyd in 'Field Sports of North of Europe' volume 1 page 387.), 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. (1/33. Quatrefages 'Soc. d'Acclimat.' May 11, 1863 page 7.) An interesting account has been given by Mr. G. Clarke (1/34. 'Annals and Mag of Nat. Hist.' volume 15 1845 page 140.) 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 singly or in packs, and burrow holes for their young. (1/35. Azara 'Voyages dans l'Amer. Merid.' tome 1 page 381; his account is fully confirmed by Rengger. Quatrefages gives an account of a bitch brought from Jerusalem to France which burrowed a hole and littered in it. See 'Discours, Exposition des Races Canines' 1865 page 3.) 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. (1/36. With respect to wolves burrowing holes see Richardson 'Fauna Boreali-Americana' page 64; and Bechstein 'Naturgeschichte Deutschlands' b.