Snakes Order Squamata, Suborder Serpentes

Venomous

All of North America's venomous snakes, except coral snakes, are pit vipers (family Crotalidae).  North American pit vipers have a deep, heat-sensitive loreal "pit" located between the eyes and nostrils of the snake (seen clearly on the copperhead), and front hinged fangs with a mostly hemotoxic venom which affects the muscle tissue and circulatory system.  Coral snakes belong to the family Elapidae, front fixed fangs with a mostly neurotoxic venom which affects the central nervous system.  Other elapids include the cobras and mambas.

Copperhead Agkistrodon contortrix	Juvenile Cottonmouth Agkistrodon piscivorus	Cottonmouth Agkistrodon piscivorus	Pigmy Rattlesnake Sistrurus miliarius	Massasauga Sistrurus catenatus
Western Diamondback Rattlesnake Crotalus atrox	Prairie Rattlesnake Crotalus viridis	Timber Rattlesnake Crotalus horridus

Nonvenomous

Family Colubridae - harmless, egg-laying snakes (oviparous)

Bullsnake Pituophis catenifer	Great Plains Rat Snake Pantherophis emoryi	Western Black Rat Snake Scotophis obsoletus	Speckled Kingsnake Lampropeltis getula	Prairie Kingsnake Lampropeltis calligaster
Racer Coluber constrictor	Plains Blackhead Snake Tantilla nigriceps	Ground Snake Sonora semiannulata	Rough Green Snake Opheodrys aestivus	Milk Snake Lampropeltis triangulum
Coachwhip Masticophis flagellum

Family Natricidae - harmless, live-bearing snakes (ovoviviparous)

Lined Snake Tropidiclonion lineatum	Western Ribbon Snake Thamnophis proximus	Plains Garter Snake Thamnophis radix	Blotched Water Snake Nerodia erythrogaster

Family Xenodontidae - robust, rear-fanged snakes

Western Hognose Snake Heterodon nasicus	Eastern Hognose Snake Heterodon platirhinos

Family Dipsadidae - slender, rear-fanged snakes

Western Worm Snake Carphophis vermis	Ringneck Snake Diadophis punctatus