Shepherds of the Wild by Edison Marshall — Read

These were not wolves. This fact dawned upon Alice Crowson, running her little flock at top speed toward the camp, before ever she saw their savage forms burst forth from the thickets behind and even before she discerned the twitch and leap of their shadows in the distant stretch of moonlit canyon. Only in the starving time of winter had wolves approached with such terrible fearlessness and frenzy. Nor was the cry that long, strange running song of the wolf pack. She knew their breed. They were enormous hounds: such a savage pack as might have started forth from some awful Underworld of fable.

And it would have been better were they wolves. Not for nothing has man waged immemorial centuries of warfare, not only upon wolves but on the great felines as well. They have been taught a wholesome respect for the tall breed that has come to dominate the earth, and much hunger and madness must be upon them before they will dare raise fang or claw against him. But it is not this way with dogs. They have lived among men since the first days of the cave dwellers; they have found men out; they have been willing slaves and faithful servants, and once the impulse comes to attack, there is no ingenerate barrier of instincts to hold them back.