the bitchmaster continued to moan in the other room , and to make occasional talking noises , but her sounds were not the source of the stray 's jitters ; they were not what had caused it to sit up when it had been on the verge of drifting placidly off to sleep , and not the reason why its good ear was now cocked alertly forward and its muzzle had wrinkled back far enough to show the tips of its teeth .