The bullsnake is one of the largest/longest snakes of North America and the United States, reaching lengths up to 8 ft.

They are known as bull snakes or bullsnakes because of the deep hissing/rumbling sound they make when nervous, which can be reminiscent of a bellowing bull, as well as their overall defensive display of rearing up like a rattlesnake and rattling their tail in leaves, all of which is a bluff; the snake is not venomous, and rarely bites.

The bullsnake (Pituophis catenifer sayi) occurs throughout the Great Plains and parts of the Midwestern United States, ranging from southern Saskatchewan, and Alberta, Canada south, into Nuevo León and Tamaulipas, Mexico.

States in the US include Colorado, Illinois, Indiana, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Wisconsin, and Wyoming.

[11] Bullsnakes are very powerful constrictors that eat small mammals, such as mice (including Peromyscus and Reithrodontomys spp.

[13] Their climbing proficiency enables them to raid bird nests (and birdhouses) to eat the nestlings or sitting mother.

Owing to its coloration, dorsal pattern, and semikeeled scalation, it superficially resembles the western diamondback rattler (Crotalus atrox), which is also common within the same range.

The end of the glottis is covered by a piece of cartilage known as the epiglottis, which flaps back and forth when air is exhaled from the right lung, producing a convincing rattling sound.

It commonly vibrates its tail rapidly in brush or leaves, and flattens its head to resemble the characteristic triangular shape of the rattlesnake.