Geographic range
Species and subspecies within the genus ''Pituophis'' are found throughout Mexico, the Southern and Western United States and Western Canada.Roger Conant (herpetologist), Conant R (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition''. Boston: Houghton Mifflin. (paperback). (Genus ''Pituophis'', pp. 198–201 + Plate 27 + figure 57 + Map 147).Description
All species of ''Pituophis'' are large and powerfully built. The head is relatively small in proportion to the body and it is only slightly distinct from the neck. The Rostral scale, rostral is enlarged and elongated, imparting a characteristic somewhat pointed shape to the head. All the species occurring in the United States have four Prefrontal scales, prefrontals instead of the usual two.Modified epiglottis
In all snakes of the genus ''Pituophis'', the epiglottis is peculiarly modified so that it is thin, erect and flexible. When a stream of air is forced from the Vertebrate trachea, trachea, the epiglottis vibrates, thereby producing the peculiarly loud, hoarse hissing for which bullsnakes, gopher snakes and pine snakes are well known.Karl Patterson Schmidt, Schmidt KP, Davis DD (1941). ''Field Book of Snakes of the United States and Canada''. New York: G.P. Putnam's Sons. 365 pp. (Genus ''Pituophis'', pp. 158–160).Species and subspecies
References
Further reading
*External links
* *Accounts of four subspecies, ''P. deppei deppei, P. deppei jani, P. lineaticollis lineaticollis'' and ''P. lineaticollis gibsoni'', are given in :fr:William Edward Duellman, Duellman WE (1960)