I recently installed a dog barking/growling sound fx app on my cell phone for use as a possible black bear deterrent when hiking/camping. Normally while hiking a trail my phone is turned off and packed away, so most of the time the app is useless, especially useless if its a surprise encounter. But while taking a break, sitting around camp or just plain lucky enough to spot the bear before it gets too close, the barking app could work. Of course the bear might not have any fear of dogs but i think chances of that are very low. What i do wonder is, if the bears hearing is sensitive enough to recognize its not a real dog barking and if that would make much of a difference...