Hypsiglena are found throughout the southwestern and western United States, from Texas and Kansas, west to California, north to Washington, and south into Mexico, as well as on islands off the coasts of Mexico.
Habitat
The preferred habitat of night snakes is semiarid desert regions with rocky and sandy soils.
Description
Night snakes typically do not exceed a total length (including tail) of 40 cm (16 in). They are slender-bodied with a flattened head, and have small eyes with vertical pupils. Their color varies depending on their locality, often matching the soil color of their native habitat. They occur in various shades of gray, and brown, with dark brown, gray or black blotches on the back and the sides. Many also have distinctive black markings on the neck region.
The diet of night snakes consists primarily of lizards, but they will also consume smaller snakes, and amphibians.
Venom
The venom of Hypsiglena is not considered to be dangerous to humans.
References
^Tanner WW (1944). "A Taxonomic Study of the Genus Hypsiglena ". Great Basin Naturalist5 (3 & 4): 25-92.
^Mulcahy DG (2008). "Phylogeography and species boundaries of the western North American nightsnake (Hypsiglena torquata): Revisiting the subspecies concept". Molecular Phylogenetics and Evolution46 (3): 1095–1115.
^Mulcahy, Daniel G.; Martínez-Gómez, Juan E.; Aguirre-León, Gustavo; Cervantes-Pasqualli, Juan A.; Zug, George R. (2014). "Rediscovery of an Endemic Vertebrate from the Remote Islas Revillagigedo in the Eastern Pacific Ocean: The Clarión Nightsnake Lost and Found". PLOS ONE9 (5): e97682.
Further reading
Cope ED (1860). "Catalogue of the Colubridæ in the Museum of the Academy of Natural Sciences of Philadelphia, with notes and descriptions of new species. Part 2". Proceedings of the Academy of Natural Sciences of Philadelphia12: 241–266. (Hypsiglena, new genus, p. 246).
