tegreptiles

I went upstairs to feed my iguana and I saw a lot of blood under his cage. (he doesn't really have a cage, just a perch by the window in my reptile room that he rarely moves from). It was a lot of blood. He didn't seem to be hurt, he was acting normally but I noticed his cloaca had some dry blood on it. I have NO idea what to make of it. He ate his food just as he always does.