I have something I would like to pass on that I read several years ago. It was written by someone of the stature of Leonard Lee Rue III, I'm not sure if he was the author. What he said was that when a prey animal is injured their brain causes their body to release a chemical that deadens pain. He had a name for it, I don't remember what he called it. I have no idea if it is true, I sure hope it is, it would be nice if nature did this for them. I do not remember reading that prey animals produce tears when injured, I would think that they do have tear ducts though, to lubricate their eyes.