According to Wikipedia, Rat snakes (or ratsnakes) are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemisphere. They feed primarily on rodents and birds. Masters patrons learned that last part first hand during the Par 3 Contest when a pretty large one (About 5 feet in length, which is 5 feet too long) fell out of a tree with a squirrel in its mouth. And yep, RIP squirrel.