''Pituophis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of non

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

colubrid Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ev ...

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

s, commonly referred to as gopher snakes, pine snakes, and bullsnakes, which are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to North America.

Geographic range

Species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

and subspecies within the

''Pituophis'' are found throughout

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, the Southern and

Western United States The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the We ...

and

Western Canada Western Canada, also referred to as the Western provinces, Canadian West or the Western provinces of Canada, and commonly known within Canada as the West, is a Canadian region that includes the four western provinces just north of the Canada� ...

. 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 is enlarged and elongated, imparting a characteristic somewhat pointed shape to the head. All the species occurring in the United States have four prefrontals instead of the usual two.

Modified epiglottis

In all snakes of the genus ''Pituophis'', the

epiglottis The epiglottis is a leaf-shaped flap in the throat that prevents food and water from entering the trachea and the lungs. It stays open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration of food in ...

is peculiarly modified so that it is thin, erect and flexible. When a stream of air is forced from the

trachea The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...

, the epiglottis vibrates, thereby producing the peculiarly loud, hoarse hissing for which bullsnakes, gopher snakes and pine snakes are well known. 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

External links