“The bullsnake (Pituophis catenifer sayi) is a large, nonvenomous, colubrid snake. It is a subspecies of the gopher snake (Pituophis catenifer). The bullsnake is one of the largest/longest snakes of North America and the United States, reaching lengths up to 8 ft.
Bullsnakes can sometimes be mistaken for rattlesnakes and killed. 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 bullsnake capitalizes on this similarity by performing an impressive rattlesnake impression when threatened.
The idea that bullsnakes occasionally eat rattlesnakes is sometimes given as a reason for humans not to harm bullsnakes when encountering them in the wild; however, a study of 1000 bullsnakes found only 2 had rattlesnake in their stomach contents, and so this is a very rare occurrence.” [see footnotes] https://en.wikipedia.org/wiki/Bullsnake
A bullsnake’s artistic impression of a rattlesnake’s characteristic “rattling” sound is nothing short of impressive. Especially considering it’s glottal origin. The young, smallish (2-3 feet) snake pictured offered an impressive, sizable performance … according to my wife who took the picture during her late afternoon walk down by the bosque.
Eideard 
“The bullsnake (Pituophis catenifer sayi) is a large, nonvenomous, colubrid snake. It is a subspecies of the gopher snake (Pituophis catenifer). The bullsnake is one of the largest/longest snakes of North America and the United States, reaching lengths up to 8 ft.
Bullsnakes can sometimes be mistaken for rattlesnakes and killed. 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 bullsnake capitalizes on this similarity by performing an impressive rattlesnake impression when threatened.
The idea that bullsnakes occasionally eat rattlesnakes is sometimes given as a reason for humans not to harm bullsnakes when encountering them in the wild; however, a study of 1000 bullsnakes found only 2 had rattlesnake in their stomach contents, and so this is a very rare occurrence.” [see footnotes] https://en.wikipedia.org/wiki/Bullsnake
A bullsnake’s artistic impression of a rattlesnake’s characteristic “rattling” sound is nothing short of impressive. Especially considering it’s glottal origin. The young, smallish (2-3 feet) snake pictured offered an impressive, sizable performance … according to my wife who took the picture during her late afternoon walk down by the bosque.
“The Sacred Hopi Snake Dance Impressed Theodore Roosevelt” https://www.historynet.com/sacred-hopi-snake-dance-impressed-theodore-roosevelt/