25-84 inches. In southern Louisiana and some low areas in central Louisiana: tan or gray with large dark brown or black blotches down the back and a smaller series on each side; some scales yellow, orange or red producing a calico effect; underside white anteriorly, grading to gray or pale brown with obscure markings towards the tail. In northern and central Louisiana: black above, often with pale spotting indicating a vague outline of dark blotches. Young rat snakes are pale gray with dark brown blotches. Scales slightly keeled on the middle of the back, and in 25-27 rows.
Rat snakes occur in most habitats in Louisiana, but seem to reach their peak abundance in areas containing a mixture of pastures, farmland and woodlands. They climb readily, and may be seen high in trees or crawling up the trunks, and in the rafters of barns. Rat snakes raise their forebody in a loose coil, strike and rattle their tail when agitated. The defensive behavior produces undue fear in some people because rat snakes are non-venomous. They lay from 4-44 eggs.
Throughout Louisiana eastward to the Mississippi River floodplain, but sparingly into the edge of the marsh country.