If you look at the end of his tail, you might notice it looks like it has something stuck on it. I think he either had it smashed or something chewed it because it looks like it has a large sore on it.

Update....The tip of Boots tale fell off during one of his baths. It looked like it had an open wound on it that we put medication on. It has healed but his tale doesn't look the same as Ahmrees. Ahmrees comes to a point where as Bootsu's looks like it is a flat top. He doesn't seem to mind though.