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Squamata, Serpentes: Dipsadidae - New World Thirst Snakes |
| Dipsadid snakes were previously regarded as members of the Colubridae. Here I am following Vidal et al.'s (2007 C. R. Biologies 330:182-187) reorganization of these snakes. They recognized three subfamilies within this family: Heterodontinae - North American Thirst Snakes; Dipsadinae - Central American Thirst Snakes; and Xenodontinae - South America Thirst Snakes. Thus, all members of this family are in the Western Hemisphere, but they had an Asian origin. Some of them have enlarged rear fangs and toxic venom, but most are harmless to humans. The name "Rear Fanged Snakes" has been applied to these animals, but snakes in other families also evolved enlarged rear teeth on the maxillary bone and not all members of the Dipsadidae have this type of dentition. The name "Thirst Snake" is based upon a direct translation of the Greek word "dipsa" meaning thirst. Most of these snakes lay eggs, but there are exceptions. |
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The Ring Necked Snake, Diadophis punctatus Baird & Girard, 1853. Photographed in Presidio County, Texas. Ring Necked Snakes range from southeastern Canada and the east coast of the USA westward to California and southward into Mexico. These small snakes may reach 700 mm, but most are much smaller. They feed on earthworms, amphibians, small snakes, and lizards. The snake in the photo is referable to the subspecies D. p. regalis. Molecular studies suggest that populations east of the Mississippi are genetically distinct from those to the west of the river.
Click the photo for more Heterodontinae snakes
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White Headed Snake, Enulius sclateri (Boulenger, 1894). Photographed in northeast Costa Rica. Found crossing a road in wet forest. Adult maximum size about 550. It occurs from Nicaragua to Panama. It feeds on reptile eggs. It has a long tail which will break off if grabbed by a predator.
Click the photo for more Dipsadinae snakes
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Amazonian Water Snake, Helicops angulatus (Linnaeus, 1758) is widespread in the Amazon Basin. This specimen was from eastern Trinidad and was found within a few hundred feet of the ocean. Adult reach at least 670 mm. It feeds on fishes and frogs, including tadpoles.
Click the photo for more Xenodontinae snakes
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