SNAKES 

 CHAPTER 12 



An extreme and largely unjustified prejudice exists against snakes. This 

 is apparently another example of the principle that we distrust whatever we 

 do not understand. It is well to beware of snakes until one has learned which 

 ones are poisonous, but fortunately these are limited to two groups, rattlesnakes 

 and copperhead, in the states north of 40° latitude. South of this two others, 

 water moccasin and coral snakes, are also found. Most snakes are inoffensive 

 or beneficial animals, streamlined for pursuing insects, rodents and other prey. 

 The visits snakes pay to barns and outdoor cellars are usually in search of 

 mice. 



A few of the li2;ards, a related group of reptiles, lack limbs and bear a close 

 resemblance to snakes. The most common of these li2;ards, the glass snake, may 

 be distinguished from the snakes by the presence of movable eyelids and ex- 

 ternal ear openings. The others are less readily identified as li2,ards. In order 

 to avoid confusion in this regard, the legless lizards have been included in the 

 snake key as well as in the preceding chapter. 



The poisonous snakes of wide distribution are the pit-vipers — the rattle- 

 snakes, the copperhead and the moccasin or cotton-mouth. These all have 

 vertical pupils or cat-like eyes, the mark of crepuscular or twilight-roaming 

 animals. They are not likely to be encountered abroad during full daylight, 

 except for short intervals in the spring or fall, as they are leaving or seeking 

 hibernation quarters. Another distinguishing character of these snakes is the 

 presence of a deep ''dimple" or pit on the side of the head halfway between 

 the eye and the nostril. They also differ from most of the other snakes in 

 having most of the subcaudal plates undivided. The poison fangs are hollow, 

 like hypodermic needles, and are situated in the front of the upper jaw. They 

 are folded back against the roof of the mouth when not in use. The poison 

 injected into the victim by one of these snakes acts on the haemoglobin of the 

 blood. 



The rattlesnake is readily recognized in the field by the presence of 

 "rattles'' on the end of the tail, which in motion produce a noise much like 

 that made by a cicada. Many harmless snakes simulate this sound by buzzing 

 the tail among sticks or dry leaves. The copperhead may be identified by the 

 "■hour-glass" back markings, narrowest on top, and by the lack of markings 

 on top of the head. The harmless milk snake or checkered adder, so often 

 mistaken for the copperhead, has its back blotches widest on top and usually 

 has a yellow, Y-shaped marking on its neck and an additional spot or two on 



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