Of course they HEAR gunshots, it' s just a question of whether they KNOW it' s a gunshot. If we' re talking about a deer that doesn' t have a lot of experience with gunfire or hunters, then they have no idea what it is, it' s just a really loud sound. And in nature, the really loud sounds don' t hurt you, i.e. thunder, falling trees, that kind of thing. It' s the quiet noises like approaching predators ruffling leaves and breaking twigs that get deer in low hunting pressure areas nervous. That' s why deer spook at a bowstring or a snapped twig but continue to feed unphased by a rifle blast under certain conditions.