bull snake

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several large, nonvenomous North American snakes of the genus Pituophis that have yellow and brown or black markings and feed chiefly on rodents.

from The Century Dictionary.

• noun A popular name in the United States for a serpent of the genus Pityophis, or pine-snake, which sometimes grows to the length of 6 feet, and makes a loud hissing noise when disturbed, but is of mild disposition and not poisonous.

from the GNU version of the Collaborative International Dictionary of English.

• noun any of several large harmless rodent-eating North American burrowing snakes of the genus Pituophis. They include the gopher snake and pine snake.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of several large harmless rodent-eating North American burrowing snakes
• noun any of several large harmless rodent-eating North American burrowing snakes