• He became quicker of movement than the other dogs, swifter of foot, craftier, deadlier, more lithe, more lean with ironlike muscle and sinew, more enduring, more cruel more ferocious, and more intelligent. He had to become all these things, else he would not have held his own nor survived the hostile environment in which he found himself.

    Jack London (2016). “Jack London Six Pack”, p.115,