llattle oj- Crotalus (.lurissus. 55 



animals refused to eat any tiling but very young rabbits), 

 I lost five of them in the course of the first six mouths. The 

 remainder are in good condition, and now (August 1888) 

 devour birds in addition to rabbits. They live in a large 

 den, provided with a cement floor and a spacious water-tank, 

 and permanently warmed by hot water, which renders it 

 possible to maintain the temperature of the air in the interior 

 at_77° to 81°-5 F. (20° to 22° R.). The snakes are provided 

 with living food in sufficient abundance, and are equally 

 lively in winter and summer. 



This opportunity has enabled me to make accurate obser- 

 vations upon the growth, shedding, and renewal of the rattle. 

 Up to the present nothing is known with certainty as to the 

 physiology of this apparatus. Throughout America, for 

 example, the inhabitants estimate the age of a Rattlesnake 

 according to the number of rings in the rattle, and they 

 believe that a new ring is added annually (Brehm), Others, 

 agaiuj consider that a new ring is formed at each ecdysis. and 

 so on. Brehm * points out that though it is true that R ;ttle- 

 snakes which have been kept in captivity and observed for 

 several years consecutively have been found to increase in 

 size, an increase in the number of the joints of their rattles 

 has not been perceived ; on the contrary, these remained 

 unchanged for years. It is likewise not definitely stated by 

 any author how long a rattle may become. I am in the 

 happy position of having been able to make certain obser- 

 vations upon healthy specimens with good appetites, which 

 decide these questions. 



Five of my snakes shed their long rattles independently at 

 different times, and I was now able especially to observe how 

 rapidly these redevelop. I would first, however, remark that 

 it is perfectly natural for the rattle of the Rattlesnake to fall 

 off periodically or at irregular intervals. The organ in 

 question consists of dead horny tissue, which is developed 

 into the well-known hollow "cones": while these cones 

 partly enclose one another, to form the rattle, they are yet 

 only somewhat loosely connected together. Now it may be 

 readily understood that such a chain of cones, when it attains 

 a certain length, is greatly exposed to mechanical shocks, and 

 consequently may easily break ofi\ Without any injury to 

 the snake itself, this chain may be also cut off or torn off' by 

 force. This is indeed the simple reason why the rattle never 

 becomes particularly long, and rattles with from fifteen to 



* Brehiu, ' Thierleben,' Bd. vii,, " Krieclitliiere,' 1883, p. 491. 



