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''Elaphe'' is one of the main genera of the rat snakes, which are found in many regions of the northern hemisphere. ''Elaphe'' are medium to large constrictors by nature. All species are nonvenomous. Although all of the species in ''Elaphe'' are nonvenomous, bites from rat snakes are still irritably painful and can potentially cause bacterial infections due to the saliva.〔 ("Rat snakes – life-cycle, predation, diet, bites, hibernation, pictures and videos." ) Ratsnake.org. (2010-09-23).〕 Based on the mitochondrial DNA analysis results, many species of ''Elaphe'' have been moved to the genera ''Bogertophis'', ''Coelognathus'', ''Gonyosoma'', ''Orthriophis'', ''Pantherophis'', ''Rhinechis'', ''Senticolis'', ''Zamenis'' and more. Nevertheless, the name ''Elaphe'' is still widely used. ==Physical characteristics== Like most of the rat snakes, ''Elaphe'' generally have slender but sturdy bodies, square heads and extremely flat bellies〔 Their sizes range from large medium to very large,〔Wright, A.H. and A.A. Wright. (1957). ''Handbook of Snakes of the United States and Canada.'' Comstock. Ithaca and London.〕 growing even as large as 108 inches. ''Elaphe'' have large numbers of vertebrae, ribs and ventral scales but few rows of dorsal scales. The dorsal scales of ''Elaphe'' are characterized by having slight keels. In cross section ''Elaphe'' are shaped like a loaf of bread, the flat belly meeting the sides of the body at an angle.〔Conant, Roger. (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America.'' Houghton Mifflin. Boston.〕 This special physical characteristic is well observed in ''Elaphe obsoleta'' whose belly scales curve upward. The curving of the ventral scales renders ''Elaphe'' better traction for tree climbing.〔 Wernert, S. J. (1982). ''Reptiles. Reader's Digest North American Wild Life''. Pleasantville, New York: Reader's Digest. p. 174.〕 The color and pattern of ''Elaphe'' is quite variable and hard to be generalized. The following are the descriptions of the color and pattern for some Elaphe species. ''Elaphe guttata'', or corn snakes, have arrow-shaped blotches on the head and black squarish blotches on the ventral side. The underside of the tail is striped.〔 Adult black rat snakes, one of the subspecies of ''Elaphe obsoleta'', are shiny black on the dorsal side with some yellow, white and red on the skin between the scales. The anterior ventral side, the throat and the neck, is white, while the posterior ventral side of the snake is marked with black and brown.〔 The yellow rat snakes, a subspecies of ''Elaphe obsoleta'', differ from the black rat snakes in that they have four bold longitudinal dark stripes. The background color ranges from dull to bright yellow.〔 Internally, ''Elaphe'' do not have any observable vestiges of hind limbs or coronoid bones of the lower jaw like any other members of the Colubridae family. Another important characteristic of ''Elaphe'' as part of the Colubridae is the presence of Duvernoy's gland, a modified salivary and digestive gland.〔 Evans, A. V., Garrison, R. W., Schlager, N., Hutchins, M., & Murphy, J. (2004). Vol 7. ''Grzimeks' Animal life Encyclopedia'' (2nd ed., p. 467). Detroit: Thomson-Gale.〕 In addition, ''Elaphe'' have equal and smooth maxillary teeth.〔 Wright, A. H., & Wright, A. A. (1994). Rat Snakes. Handbook of Snakes (pp. 209,218,220). Cornell University Press.〕 The teeth are small and slightly curved and are placed in several rows. The curvy teeth help fixate the prey and prevent them from escaping once they are caught.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Elaphe」の詳細全文を読む スポンサード リンク
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