I am not sure what it is I but, I have seen more then one deer run 200 yards out on a heart shot, and never was it chased. We wait half an hour to one full hour before pursueing a shot deer. I have also had them run as far as 300 yards on a lung shot and fall over a fallen tree. Some deer just run until they fall over. Where they fall is where they fall. Or maybe Maine deer are stronger or something, because most will run themselfs out once hit up here.