ine species; from several races or
species of the jackal; and perhaps from one or more extinct species. Those
authors who attribute great influence to the action of climate by itself
may thus account for the resemblance of the domesticated dogs and native
animals in the same countries; but I know of no facts supporting the belief
in so powerful an action of climate.

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,[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 ha