Population of small animals, there's an increased risk for mutation. so that's why this these groups -- in these groups of animals, you're seeing this. i don't like bats, they look kind of strange, but if you think of to them as birds, they're a little easier to sort of understand. jon: and the fear is, we're not talking vampire bats, but the fear is it could get into humans how? >> well, one of the things that they're looking at in china is having people no longer capture bats for the food i have. believe it or not, this is done because when humans interact with bats, there's a risk of respir...