The Rattlesnakes 



dog colony has been prompted by a hungry stomach. It does 

 not hesitate to prowl into a burrow and devour several of the 

 young. It does not remain in the burrow for the warm, animal 

 odour of the place warns it that the parent has but shortly left, 

 and while it does not fear an encounter it craves a quiet place 

 where it may assimilate the meal. Crawling forth into the sun 

 again, it wanders about in search of a deserted burrow and into 

 this it disappears for several days. It is at the mouth of this bur- 

 row, placidly sunning and awaiting the completion of digestion 

 that the human observer sees the snake. Nearby may be an- 

 other burrow, for some time deserted by the original occupants 

 and now occupied by a family of owls. Nothing could be more 

 incongruous or farther from harmony, than a mixture of snake, 

 "dogs" and owls in the same burrow. 



THE PACIFIC RATTLESNAKE 



Crotalus oregonus, (Holbrook)* 



Size rather smaller than the prairie rattlesnake. The 

 greater number of specimens are under four feet in length. The 

 conformation is much like that of the allied species. 



Colouration.— Very similar to the prairie rattlesnake. The 

 ground-colour is gray, pale brown or greenish. On the back are 

 large, rounded spots, well separated and narrowly bordered with 

 black; toward the tail these blotches fuse into the shape of 

 transverse bands; the tail is more strongly barred with the darker 

 colour than that of the other species. 



Head markings. — The markings of the head appeal to the 

 prairie rattlesnake, but may be readily employed to distinguish 

 the present species. The dark band commences behind the 

 centre of the eye and extends to the angle of the mouth — with 

 C. confluentus it begins beneath the centre of the eye. The 

 pale band in front of this darker one is much broader than with 

 the prairie rattlesnake. 



Although the large eye plates on the top of the head have 

 symmetrical, pointed marks, which terminate at the outer margin, 

 these are not vividly defined. 



* Has erroneously been called Crotalus lucifer, (B. & G.)- Because 

 Holbrook's original figure portrayed a rhoinb-like pattern, numerous 

 writers have refused to accept it as representing this species, though 

 Holbrook designated the locality, and the scalation of the head of the 

 tvpe specimen agrees with the description of lucifer. 



4S8 



