Poisonoui Snak»t of the World 



IS N|i««cilic I'tir ll(i> MMioiiis of tlio I'lislern ami 

 wi'sU'i'ii (liumoinllmfks {('rotiihis (ulamnntcHi^ and 

 ('. iifroj-). It is I'llVctive to sniiu' il('<;i'iH' uf^ainst 

 all lattlosnako vcnoins. 



'riu> larjit-r sin'cii-s of rattlosuaki's fcfd piin 

 cipally ii|iui) small iiiainiiiais; llio smaller species 

 mostly upon lizards. All iiittli-snidios uro livc- 

 lioariiijj. 



CROTALIDAE: Genus Crofalus Linnaeus, 1758. 

 Uaillesiiakes. 



Genus Crotalus Linnaeus, 1758. Rattlesnakes. 



Alioiit 2r> siwcics uf riittlfsiiiiki's ari' riini'iilly recog- 

 iii/.i-d. .Most spt'i-ios arc in tlu> .soiitli western I'liited 

 States ami nurtlu'i'ii Mexico. One si)eii,-s (C. duriasus) 

 rnnses soutliwanl into soutliern South America, two are 

 found east of tlie Mississippi River, and two as far 

 nortli as Canada. .V few of the very snuill species, and 

 small individuals of larKe species (less than 2 feet) 

 may otTcr little daniicr. but most species do; some are 

 hifilily dangerous. 



Di/inilioii : Head liioad, very distinct from narrow 

 neclc, canthus distinct to absent. Body cylindrical, de- 

 pressed, or slightly compressed, moderately .slender to 

 stout; tail short with a horny segmented rattle. 



Eyes small: pupils vertically elliptical. 



Figure 12. — Head of Eastern Diamoiidback Kattlesn.ike, 

 CrotaliiK fiflanimitrii.i, showing absence of many crown 

 scutes. Drawing by Lloyd Sandford. 



Head scales : Supraoculars present, a pair of iiiterna- 

 sals often distinct, occasionally a pair of prefrontals; 

 enlarged canthal scales often present ; other parts of 

 crown covered with small scales. Laterally, eye sepa- 

 rated from supralabials by 1-5 rows of small scales. 



Bod.v scales : Dorsals keeled, with apical pits, in 

 19-.3.3 nonoblique rows at midbody. Ventrals 1.32-206; 

 subcaudals 13— t."i. all single or with some terminal ones 

 paired. 



Eastern Diamondback Rattlesnake, ('ailiihis mlu- 

 iiiiin/riis Hcau\()i>. 



lilinliflratiiiit : Within its niiigc the only large rattle- 

 snake with distinct, diagonal, whitish strljies on sldo of 

 bead; tall more or lesH Indistinctly ringed. 



Olive green to dark brown with central .series of 

 darker diamond shaped blolches each with a soniewliat 

 lighter center and a distinct cream oi- ycllnw edge; belly 

 cream heavily clouded with gray. 



Average Icnutli .3'j to .">'/• feet; mMxinmiii s feet. 





Figure 13. — Eastern Diamondba<k Rattlesnake, CrotahiH 

 adainoitcH.i. Photo by Isabelle Hunt Conant. 



Dislrihiilioii : t'oastal lowlands from North Carolina 

 through Florida to extreme eastern Louisiana. Found 

 in dry pine woods, palmetto thickets, old fields. How- 

 ever, may enter w;iter. either fresh or salt. 



Western Diamondback Rattlesnake, CrofaJus atrox 

 Baird tind Girard. 



Idrntifiratioii : Two light, diagonal stripes on side of 

 head, posterior one extending to angle of mouth; tail 

 distinctly ringed with black and gray or white, tlie black 

 rings as wide as or wider than the pale ones ; scales 



Figure 14. — Western Diamondback Rattlesnake, Cro- 

 talus atrox. Photo courtesy Scientific American. 

 (See also plate III, fig. 2). 



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