Is it ensure, insure, or assure?
North American constrictor snake of the family Colubridae. These snakes are called bull snakes over much of their range; however, in the western United States they are often called gopher snakes. Bull snakes are rather heavy-bodied, small-headed, and may reach 2.5 metres (8 feet) in length. Typical coloration is yellowish brown or creamy, with dark blotches. The nose shield is enlarged for digging. They are related to pine snakes (P. melanoleucus) of the eastern and southern United States and the Mexican bull snake (P. deppei) of north central and western Mexico