Don't know how big they are "supposed" to get but when I was kid back in early 60's on our farm, I saw two of em drag our full grown Collie down their burrow! Didn't see Prince for three days. When he returned he was all bit up and could hardly walk. He never chased
a ground hog after that. Whenever he saw that pair he would run and hide in the barn just a whimpering and a drooling. Strangest thing I ever saw.