Yes, I was/am very worried about internal damage. The gut is covered in tiny little villi that are like little microscopic fingers. The hair was folded such that the loop end was last, so it was being dragged out, possibly catching on the villi and other structures in the gut. I only noticed it because a tiny bit of urate had dried on it a half an inch from his body. I'm sure it is a hair--my hair no less--because I put both my hair and what I cut off that was sticking out his vent under a microscope. I'm no forensic scientist but they sure looked the same to me when compared side by side. I agree, what are the odds of that?