Poiionoui Snakoi of (he World 



■ iiily ) or koili'il. with uiilral pits. In 17 "JT iii>iicilill(|iic 

 rows. Vfiilriils l-T. 171: suln-iiiuliils sliiulo unli'rldrly 

 iir imirt'il thnniKliixit. 21 -tis. 



Cantil, Aijk-istioiloii hilliii'iifus fiiiutlicr. 



Iiltntiflriiliiin : A rliocoliitf-lirowii ti> black pll vIimt 

 Nvltli (yplriil lii'ailphili's iiiiil oiii' Ihlii liulil lirii' iiloiiu IIk' 

 I'linlliiis, cDiitluuiim lifliliul till' cyt', aiicilhcr alimi; tln' 

 ii|iper part of tlu' suprulnbials to tlu> coriu-r of the 

 iiiduth. Adults avfi-nne 2 1/2 to 3 fct't ; occasininil in- 

 ilividiials excood 4 fct't. 



.luvciiilf individiinls liavp broad liKlit-('d>;cd crossliaiids 

 nil a liublcr tia(k;;iouii(l ; tbesi- disappear in adults ex- 

 cept for traces of the while cdKiuK whicli persist as 

 luirrow irregular crossbars of while cducd scales. Ven- 

 tral color dark brown with lilaik-cdi;cd while luarkincs. 



■'■J'-y.^ 



, -w -, ' L 





FlGfRE 27.- -Cantil, A(;lcittni(lnn hilhicatu.s. Photo by 

 New Vork Zoological Society. (See also plate I, tig. 4.) 



Dorsals heavily keeled, in 23-25 row.s at midbody, 

 fewer posteriorly. Ventrals 129-144 ; subcaudals 59-68, 

 the anterior 20 or so single, the posterior ones paired. 



Distrihiition : In swampy areas and along stream 

 banks on both coasts of Mexico and Central America 

 from Xiievo Leon and Sonora southward to the west 

 coast of Guatemala and the east coast of Nicaragua. 



Remarks: This is the only snake within its range 

 with the brown color and twin light stripes on the sides 

 of the head. It is aquatic and is often found swimming. 

 It is presumed to be a dangerous snake ; it is reported 

 to cause serious local lesions but seldom death. 



CROTALIDAE: Genus Bothrops Wagler, 1823. 

 American lance-lieaded vipers. 



Between 40 and 50 species are currently recognized ; 

 all are found in tropical America and southern South 

 America. There are three general groups : 1. Large, 

 long-tailed terrestrial species, usually \Yith paired sub- 

 caudals ; 2. Small, short-tailed terrestrial species with 

 single subcaudals ; and 3. Small to moderate-sized ar- 

 boreal species with prehensile tail, most of which have 

 at least the anterior subcaudals single. The large ter- 

 restrial .species are very dangerous, the others less so. 



Definition: Head broad, flattened, very distinct from 

 narrow neck; a sharply-distinguished canthus. Body 



cyllndrlcnl or nio<|cnilcly i ipressed. moderately ^^Icndcr 



lo stout : tail short to nio<leralely long. 



Kyes siiinll Ui nKMlcnilc in >l/c; pupils vci'liially el 

 liptlcal. 



Ili-ad scales: Supraoculars generally present, liiter- 

 luisals often dlsllnct, .sometimes separated by small 

 scales; remainder of crown covered with small Imbricate 

 scales: cidargcd canthals sometimes i)reseiit. Laterally, 

 second supralabial may make up anterior border of 

 loreal pit or may be separaled frnm ii. I.mciil scales 

 present or absent. 



Body scales: Dorsals keeled, in 1!> .'{5 noiioblicpie 

 rows at midbody. \'entrals 121-2."):{; subcaudals single 

 or paired, 22-83. 



Barba Amarilla, liothrops iifrox (Linnaeus). 



liUntifiniliiin : An olive-green, gray, or brownish 

 snake with a pattern of lateral darker (usually) black- 

 edged triangles whose apices meet, or nearly meet, at 

 the vertebral line. Adults average 4 to 6 feet ; record 

 lengths exceed 8 feet. 



Ground color brownish, olive, or tan, with a narrow 

 dark postorbital stripe and a series of about 20-30 

 paired lateral triangles. Each marking is lighter in 

 the center and often has a light edging to the dark- 

 bordered triangle. Ventral surface light cream to yellow 

 with dark blotches becoming more numerous posteriorly. 

 Ventrals 180-220; subcaudals 46-73, all paired. 



Dixtrihiition: Forest areas from southern Tamauli- 

 pas and southern Sonora, in Mexico, through all of 

 Central America, and in South America southward to 

 Peru and northern Brazil. A very widespread species 

 that is common in banana, coffee, and cocoa plantations 

 as well as in undisturbed forest regions ; often found 

 along streams. 



Figure 28.— Barba Amarilla, Bothrops atrox (an indi- 

 vidual from Trinidad). Photo by New York Zoo- 

 logical Society. 



Remarks : This snake has long fangs and a highly 

 toxic venom. It is probably responsible for more deaths 

 in the Americas than any other snake. It will usually 

 retreat if given the opportunity, but becomes aggressive 

 if disturbed and will strike repeatedly. 



Polyvalent antivenins for the bite of this snake are 

 produced by Laboratorio Behrens ( Venezuela ) , Institute 

 Butantan (Brazil), and Wyeth, Inc., Philadelphia. 



54 



