I have had it happen hunting around home. With all of the backround noise from the neighborhood, I don't think they heard the shot. And as fast as todays bows are, the arrow zips right thru them. They don't even feel it if it doesn't hit a bone or major muscle. They just go on until the run out of blood and tip over. That is one of the coolest sights I have had while hunting.

My bear was the same way. He was climbing up the side of a tree chewing on a beaver carcuss. My arrow zipped thru him. He flinched a little, backed down the tree and started walking toward the tree I was in. I grabbed another arrow and was getting ready to shoot him again, When he just started getting wobbly and laid down and went to sleep forever. I have that whole experiance on film too. That was a very special hunt.