Poisonous Snakes of tho World 



INTRODUCTION 



Tho poisonous smikes of South Anii-ricii lu-loii^j 

 to fi\»> jii'iuM'ii, only ouo of which (/.t/>f(>iiiiiTiirii>:) 

 is ivstrirtt'il to this i-ontiuiMit. All hul the rattii' 

 siuike jjeiuis Crotalns. however, ;ue restricted to 

 tho American tropics and IciiiiuM'ate Snutli 

 America. 



Although the hushmaster [Lachesis mtttiis) is 

 the hiiirest poisonous snake of the region, it is 

 one of the niiiioi- hazards to iiunian life since it is 

 iiKiiiily of noctuiMiai liul)it and is sluggisli or 

 secret i\o during the ilay. Tlie tropical rattle- 

 snake {CrotaJus (hi rixsus) and the large lance- 

 headeil vipers such as Bothrops atrox and related 

 species account for most of tlie deaths in tlie 

 region. 



Coral snakes (Mtcniriis and Leptomicninii) 

 are relatively common in tropical regions. Ahout 



.'](> species ai-e found iicrc 'I'liey are secretive 

 dui'ing tli(^ day and can^c relatively few cases of 

 sind<el)ile. Ilowexcr, they secrete venom of a 

 highly poisonous, neuroto.xic variety which is re- 

 sponsihlo for a very high percentage (almost 50 

 percent) of deaths in victims of their hites. 



The islands of the Carilihean wiili ii lew ex- 

 co])tions ai-e free of poisonous snakes. .VII of the 

 (ireatei' Antilles (Cuha, Jamaica, IIis|)aniola, 

 and Puerto Kico) arc fi-ce of poisonous kinds. 

 Oidy Martinique and Santa Lucia, among tlie 

 Lesser Antilles, have poisonous snakes, as do tlic 

 continental islands of Margarita, Trinidad, and 

 Tobago, and tiie offshore island of .Vruha. 



On the mainland, oidy the highest of the Andes 

 are free of poisonous snakes. At least one kind 

 of poisonous snake ranges soutlnvai'd onto the 

 pampas of southei'u Argentina, leaving only the 

 southernmost tij) of South America and the arid 

 [ilains of Chile five of venomous snakes. 



B 



KEY TO GENERA 



. Dorsal scales at midhody distinctly keeled 7 



. Dorsal scales at midbody smooth 2 



. Pupil of eye distinctly vertically elliptical NP* 



. Pupil of eye round 3 



. A loreal scale present (3 scales between nostril and eye) NP 



. No loreal scale 4 



. Color pattern of body made up of alternating rings of 

 red, yellow, and black (red restricted to head and 



tail in some) 5 



. Color pattern not in rings 6 



. Black rings alternating witli yellow; OR single, sepa- 

 rated by broad bands of red and yellow ; OR in 



triads separated by broad bands of red Mienm/s 



. Black rings in pairs or single, separated by broad rings 



of redl NP 



. A yellow band across back part of head; body black 

 above, with numerous crossbands of red or yellow- 

 below which extend u]) sides as triangles Lepfomicrurus 



. Pattei'n not as described above NP 



. With a loreal pit (fig. 4) 8 



. No loreal pit NP 



. With a segmented rattle at the end of the tail Crotalus 



. No rattle 9 



Terminal subcaudals divided into short spines, forming 



a "burr" (fig. 32) Laehesls 



. No such burr Bothrops 



NP = Nonpoisonous 



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