248 DENIZENS OF THE DESERT 



The outstanding feature of uniqueness which 

 readily separates this from all other rattle- 

 snakes, and which gives to the sidewinder his 

 vernacular name, is his peculiar mode of pro- 

 gression. Instead of moving forward in the 

 manner of ordinary snakes, he moves away 

 sidewise, keeping in the meantime his broadside 

 always toward the observer a motion which 

 is especially advantageous in carrying him over 

 the sands. It is a somewhat looping movement 

 and the tracks which are left in the sands are 

 peculiarly different from those of all other 

 rattlesnakes, being not continuous, but dis- 

 jointed, and resembling a series of colonial .//"'s, 

 each separated by a space of three or four 

 inches. Sidewinders apparently have a special 

 fondness for crawling along in wagon tracks, 

 and it is here where I have most often noticed 

 the peculiar marks. 



All other rattlesnakes must coil at least to 

 some extent before they strike, but this erratic 

 snake strikes "on the run," securing leverage 

 for his head by arching the neck, after the fash- 

 ion of a swan. This gives him an unmeasurable 

 advantage over his other crotaline cousins and 



