To address the other commenter's question about whether timberwolves pay any attention to other wildlife--i think I heard them attacking rabbits once or twice, but I do not think they had detected me.

It seems that once they detect you, they pay no attention to anything except a tasty surivivor on the ground. The TWs may also be temporarily deaf and blind at that point, since you basically need to shoot each one squarely in the face for them to acknowledge bullets or emergency flares. The gun going off three feet from their head hardly fazes them in hard mode.