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''Diadophis punctatus'', commonly known as the ring-necked snake or ringneck snake, is a harmless species of colubrid snake found throughout much of the United States, central Mexico, and southeastern Canada. Ring-necked snakes are secretive, nocturnal snakes, so are rarely seen during the day time. They are slightly venomous, but their nonaggressive nature and small, rear-facing fangs pose little threat to humans who wish to handle them. They are best known for their unique defense posture of curling up their tails, exposing their bright red-orange posterior, ventral surface when threatened. Ring-necked snakes are believed to be fairly abundant throughout most of their range, though no scientific evaluation supports this hypothesis. Scientific research is lacking for the ring-necked snake, and more in-depth investigations are greatly needed.〔O'Donnell RP, Staniland K, Mason RT. 2007. Experimental evidence that oral secretions of Northwestern Ring-necked Snakes (''Diadophis punctatus occidentalis'') are toxic to their prey. ''Toxicon'' 50: 810–815.〕 It is the only species within the genus ''Diadophis'', and currently 14 subspecies are identified, but many herpetologists question the morphologically based classifications.〔 ==Description== Ring-necked snakes are fairly similar in morphology throughout much of their distribution. Its dorsal coloration is solid olive, brown, bluish-gray to black, broken only by a distinct yellow, red, or yellow-orange neck band.〔Stebbins RC. 2003. ''A Field Guide to Western Reptiles and Amphibians, Third Edition''. The Peterson Field Guide Series ®. Boston and New York: Houghton Mifflin Company. xiii + 533 pp. ISBN 978-0-395-98272-3. (''Diadophis punctatus'', pp. 345–346 + Plate 46 + Map 133).〕 A few populations in New Mexico, Utah, and other distinct locations do not have the distinctive neck band.〔 Additionally, individuals may have reduced or partially colored neck bands that are hard to distinguish; coloration may also be more of a cream color rather than bright orange or red.〔 Head coloration tends to be slightly darker than the rest of the body, with tendencies to be blacker than grey or olive.〔 Ventrally, the snakes exhibit a yellow-orange to red coloration broken by crescent-shaped black spots along the margins.〔 Some individuals lack the distinct ventral coloration, but typically retain the black spotting.〔 Rarely, do individuals lack both the ventral and neck band coloration; so the use of those two characteristics is the simplest way to distinguish the species.〔 Size also varies across the species' distribution. Typically, adults measure 25–38 cm (10–15 in) in length,〔 except for ''D. p. regalis'', which measures 38–46 cm (15–18 in).〔 First-year juvenile snakes are typically about 20 cm (8 in) and grow about 2–5 cm (0.7–2.0 inches) a year depending on the developmental stage or resource availability.〔 Ring-necked snakes have smooth scales with 15–17 scale rows at midbody.〔 Males typically have small tubercles on their scales just anterior to the vent, which are usually absent in females.〔 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「Ring-necked snake」の詳細全文を読む スポンサード リンク
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