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					 			      	Viperidae - Wikipedia, the free encyclopedia
					 			      	 
 The Viperidae (vipers) are a family of venomous snakes found all over the world, except in Antarctica, Australia, New Zealand, Madagascar, Hawaii, various other isolated islands, and north of the Arctic Circle. https://en.wikipedia.org/wiki/Viperidae
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					 			      	ADW: Rhinoceros Viper - Bitis nasicornis
					 			      	 
 Bitis nasicornis can be found in the tropical forests throughout Central and Western Africa. Reports as far as Southern Zaire have been documented http://animaldiversity.org/accounts/Bitis_nasicornis/
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					 			      	ADW: Desert Horned Viper - Cerastes cerastes
					 			      	 
 Sahara horned vipers are among the most abundant and easily distinguishable of the venomous snakes of the North African and Middle Eastern deserts. http://animaldiversity.org/accounts/Cerastes_cerastes/
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					 			      	Pit Viper - Encyclopedia
					 			      	 
 The largest group of pit vipers is the rattlesnake, found in North, Central, and N South America. http://www.encyclopedia.com/topic/pit_viper.aspx
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					 			      	BBC Nature - Vipers videos, news and facts
					 			      	 
 Vipers are venomous snakes whose long, hinged, hollow fangs inject deadly toxins. http://www.bbc.co.uk/nature/life/Viperidae
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					 			      	Vipers - Viperidae - The Animal Encyclopedia
					 			      	 
 Vipers are a group of snakes that include true vipers, bush vipers, rattlesnakes, pit vipers, adders and night adders. http://animals.about.com/od/Snakes/p/vipers.htm
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					 			      	Pit Vipers - Snake Facts
					 			      	 
 The pit vipers are a group of venomous snakes, with a heat sensing system to help them detect prey. http://snake-facts.weebly.com/pit-vipers.html
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					 			      	Pit Vipers - Info About Pit Viper Snakes
					 			      	 
 Pit vipers are venomous snakes that use heat-sensing pits to hunt their prey. These amazing snakes can be found on several continents, and in a wide variety of habitats. http://www.reptileknowledge.com/squamata/pit-vipers.php
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					 			      	Viper - Snake - Britannica
					 			      	 
 Pit vipers are distinguished by a temperature-sensitive pit organ located on each side of the head midway between each nostril and eye. http://www.britannica.com/animal/viper-snake
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					 			      	Snake Facts - Pit Vipers
					 			      	 
 Fun facts for kids including photos and printable activity worksheets; suitable for Kindergarten through Grade 6. http://www.kidzone.ws/lw/snakes/facts11.htm
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					 			      	Pit Viper Snake Facts
					 			      	 
 About 2,500 different species of venomous snakes live throughout the globe. With the exception of a few, these species belong either to the Elapidae or Viperidae families. http://animals.mom.me/pit-viper-snake-4957.html