#pit_viper__pitviper  New World vipers with hollow fangs and a heat-sensitive pit on each side of the head
  supertype:  viper  venomous Old World snakes characterized by hollow venom-conducting fangs in the upper jaw
  member of:  family_Crotalidae
  subtype:  copperhead__Agkistrodon_contortrix  common coppery brown pit viper of upland eastern United States
  subtype:  cottonmouth__water_moccasin__watermoccasin__cottonmouth_moccasin__cottonmouthmoccasin__agkistrodonpiscivoru  venomous semiaquatic snake of swamps in southern United States
  subtype:  rattlesnake  pit viper with horny segments at the end of the tail that rattle when shaken
     subtype:  diamondback_rattlesnake__diamondbackrattlesnake__diamondback__crotalusadamanteu  large deadly rattlesnake with diamond-shaped markings
     subtype:  timber_rattlesnake__banded_rattlesnake__Crotalus_horridus_horridus  widely distributed in rugged ground of eastern United States
        subtype:  canebrake_rattlesnake__canebrakerattlesnake__canebrake_rattler__canebrakerattler__Crotalus_horridus_atricaudatus  southern variety
     subtype:  prairie_rattlesnake__prairie_rattler__Western_rattlesnake__Crotalus_viridis  widely distributed between the Mississippi and the Rockies
     subtype:  horned_rattlesnake__sidewinder__Crotalus_cerastes  small pale-colored desert rattlesnake of southwestern United States; body moves in an S-shaped curve
     subtype:  Western_diamondback_rattlesnake__Western_diamondback__Crotalus_atrox  largest and most dangerous North American snake; of southwestern United States and Mexico
     subtype:  rock_rattlesnake__Crotalus_lepidus  mountain rock dweller of Mexico and most southern parts of United States southwest
     subtype:  tiger_rattlesnake__tigerrattlesnake__Crotalus_tigris  having irregularly cross-banded back; of arid foothills and canyons of southern Arizona and Mexico
     subtype:  Mojave_rattlesnake__Crotalus_scutulatus  extremely dangerous; most common in areas of scattered scrubby growth; from Mojave Desert to w. Texas and into Mexico
     subtype:  speckled_rattlesnake__Crotalus_mitchellii  markings vary but usually harmonize with background; of sw Arizona and Baja California
     subtype:  massasauga_rattler__massasauga__Sistrurus_catenatus  pygmy rattlesnake found in moist areas from the Great Lakes to Mexico; feeds on mice and small amphibians
     subtype:  ground_rattler__massasauga__Sistrurus_miliaris  small pygmy rattlesnake
  subtype:  fer-de-lance__Bothrops_atrops  large extremely venomous pit viper of Central and South America

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