Until recently I would have said that Bella wasn't afraid of anything. A few days ago she was barking at the back fence and I came out to investigate. There was a black kitty on the other side of the fence and he was not being intimidated by her at all. At one point he hissed at her and she turned and started to run away--unfortunately straight into me (my knee) as I was walking up to her. OUCH! The funny thing is that she lives with two cats, although she has never heard a hiss out of either one of them.