Recognition of Poisonous Snakes 



A 



B 



C 



Figure !). — Appparauce of ventral plates in various groups of snakes. A. I'^xlending full width of belly (most snakes) : 

 H. Moderately rediu-ed (boas, pythons, some aquatic snakes): C. MarUtnlly reduced (many sea snakes). 



ratliof lat-ofo flesliy stfUPttires bpariiij; spiiips or 

 oilier ornamentation, l)ut tliev may he quite 

 smootli, small, and slender. 



tern and (^oloi'.s of yonn<r snakes may he totally 

 dill'erent from those of the adult. Sex differences 

 in color and pattern are also seen. 



Color and Pattern 



Color and iiatlcrn are the most widely used 

 but, iinfortiinntely, are the most deceptive ci-iteria 

 for snake identilication. Color and ])atterns in 

 snakes have evolved piimaiily f<ir ]iiitpose of 

 concealment and, as a result, totally luirclated 

 snakes may a])])ear very much alike. Afany tree 

 snakes, for cxampli\ are o-i-pon with a. litrht line 

 on the flank, and many snakes that li\c in the 

 crevices of roc^k or under hark have dark heads 

 with a liirht collar at the nape. IJeal or apparent 

 mimicrA' of venomous snakes by harmless sjiecies 

 is very widespread and may involve similarities 

 in behavior as well as ajipearance. Color and 

 pattern vary pivatly even within a species. Ii\ 

 snakes of semiarid lands, it has been observed for 

 centuries that there is often correspondence of 

 general body color with the color of the soil. 

 Abnormal increases of dark pigment (melanism) 

 or its complete absence (albinism) can in rare 

 cases give rise to black coral snakes or white 

 rattlesnakes. Pattern is generally more constant 

 than color, but several kinds of snakes may show 

 both ringed and striped types of pattern. Pat- 



Fic.uRE 10. — Undersides of tails of representative snakes. 

 Snake with ENTIRE anal plate and a SINGLE row 

 of subcandal scutes: snake with DIVIDED anal plate 

 and PAIRED rows of subcaudal scutes (V = ventral 

 plates). 



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