Barking of Dogs.
The Australian dog never barks; indeed, Gardiner, in his "Music of Nature," states "that dogs in a state of nature never bark; they simply whine, howl and growl; the explosive noise is only heard among those which are domesticated." Sonnini speaks of the shepherd dogs in the wilds of Egypt as not having this faculty; and Columbus found the dogs which he had previously carried to America to have lost their propensity for barking.