REPTILES. 387 



Thomas Morton, in his ' New English Canaan ' of 1632 says, " There is one 

 creeping beast, or creeple (as the name is in Devonshire), that hath a rattle 

 at his tayle that doth discover his age." The idea is, however, like many 

 another existing in common folk-lore, erroneous. The animal may molt 

 several times a year, or the rattles may be lost without leaving any appar- 

 ent indication of the fact, and in either case any estimate of age would 

 contain an important element of error. 



What purpose the rattle plays in the economy of the snake is not easy 

 to see. One hypothesis after another has been advanced, but to each there 

 is a more or less obvious objection. The snake, when alarmed, vibrates 

 its rattle so rapidly that one cannot trace its motions, all that is visible 

 being a haze of light. The crepitating noise produced is not easily 

 described. It has been compared to the song of the cicada, but the resem- 

 blance is not perfect. 



First among the theories advanced is that the rattle is used as a lure, 

 and that its note attracts insect-eating animals within reach. At first 

 sight this may seem probable, but a little consideration shows that it is 

 not. It supposes an evolutionary process for which there is no adequate 

 cause, and we know that nature does not work in that way. And besides, 

 when hunting, the snake does not sound its alarm. It rather moves 

 stealthily along in perfect quiet, or it lurks in ambush, and waits until its 

 prey ventures within reach. 



More probable is the view that the rattle is protective, and that its 

 warning prevents the snake from accidental injury by forms capable of 

 harming it. " The noise itself may not be instinctively fear-inspiring, nor 

 perhaps is the growling of a lion, but in each case experience has taught 

 men and the larger quadrupeds that that growl and this rattle mean not 

 only a willingness to defend, but the certain 

 ability to do deadly harm. This menacing 

 message, clicked from the vibrating tail, has 

 caused many a man to turn back and give the 

 snake a chance to escape." 



A third and still more probable view is 

 that the rattle serves as a sexual call, com- 

 bined with the function of defence just alluded 

 to. It has been noticed time and time again, 

 with these snakes in confinement, that when fig.^42.— Dissected head of a rattie- 

 one springs his rattle, all the others exhibit jjf i e t£llf tig (/J.™ {p) 

 evidences of their being excited or alarmed, 



one can scarcely say which in some instances. In some snakes the sexes 

 are called together by smell, in others by a hissing or blowing noise ; but 



