The Rattlesnakes 



Dimensions. — Occasional specimens six feet in length are 

 taken, and sometimes, though very rarely, seven-foot specimens 

 are recorded. All of the records for these very large specimens 

 seem to come from Texas. Records from various localities 

 prove interesting conditions regarding dimensions, for there 

 appear to be several races of the species, some dwarfed and sel- 

 dom growing to a length of four feet; others averaging a length 

 of five feet with quite slender bodies; while from some localities 

 all of the snakes develop to a considerable size and are more thick- 

 set than the former reptiles. From several dozen Texas spec- 

 imens an average has been figured, and follows: 



Total Length 4 feet, 6 inches. 



Tail, without rattle. . 3f 



Diameter of Body 2\ 



Width of Head. .' i J " 



Length of Head 2| " 



Length of Rattle, 10 segments 2 J " 



Disirihidion. — The species occurs principally in the sub-arid 

 and desert regions of Texas and the Southwest. It is found 

 commonly in central and western Texas, southern New Mexico, 

 Arizona and southern California. Although it may be said to be 

 most abundant in Texas where it occurs over a large area, it is 

 the most common rattlesnake of the genus throughout the en- 

 tire range. Its habitat extends well into the Tableland of Mexico, 

 but in this part of the range a peculiar phase of colouring and scu- 

 tellation of the head, is treated in a succeeding description. 



Habits. — Like the Southeastern Diamond-back Rattlesnake, 

 this is a nervous and irritable serpent, but as a captive is more 

 hardy. It will take rats, rabbits, guinea pigs and birds. An 

 example seventy-three inches in length has lived in the reptile 

 house of the New York Zoological Park for over four years. 

 The snake is given a half-grown rabbit regularly, every week. 

 Unless preparing to shed its skin it never refuses the morsel. 

 When the snake arrived from Texas, it was particularly vicious 

 for one of its species, literally hurling the body into a coil and 

 striking repeatedly at its keeper — and it has remained so. In 

 spite of the four years' attention Keeper Snyder has given it, 

 in the cleaning of the cage and presenting the food, the creature 

 strikes immediately as the door is slid back. A step in the 

 passageway behind the cages causes this dangerous brute to 



453 



