SNAKES. 45 



harvest-fly, Cicada tibicen L., or by certain species of 

 grasshoppers, and have thought that the noise was 

 made to " decoy insect eating birds into the range of 

 the serpent's spring." Others have claimed that it 

 was a love call used in bringing the sexes together. 

 Still others have looked upon it as a " providential 

 arrangement to prevent injury to innocent animals 



Fig. 13 Rattle of Banded Rattle-snake, (After Garman.) 



and man." The most commonly accepted theory at 

 present is that it is used by the snake as a " means of 

 self-protection, serving the same purpose as the growl 

 of a tiger when threatened with danger. The snake 

 seldom sounds its rattle until it considers itself discov- 

 ered, and not then unless it apprehends danger. It 

 throws itself in position to strike and says in unmis- 

 takable language: 'Look out for yourself,. I am ready 

 for you. Your life, if you injure me.' If pushed 

 upon it makes its leap at its antagonist, and again 

 throws itself in position to renew the conflict, once 

 again sounding the note of defiance."* In making 

 its warning note the snake doubtless frightens away 

 many enemies which by experience have learned to 

 shun its presence. In this way it saves its venom, foi 

 the use for which it is most evidently secreted- -that 

 of quickly destroying or rendering helpless those 

 forms of life which the reptile needs for food. 



* Henderson, J. G., American Naturalist, VI., 1872, 261, 



