REPTILES OF THE REGION 169 



north and east, but occur also in the general region of 

 the cave. They are smaller and duller colored than the 

 diamond-back, or the black-tail, with no very dis- 

 tinctive markings. 



Non-poisonous snakes of the Carlsbad Cave region 

 include the western bull snake (Pituophis sayi) (Fig. 

 58), the Mexican black snake (Drymarchon corias 

 melanurus), the coachwhip snake (Bascanion, species 

 not determined), the ring-necked snake (Diadophis 

 regalis regalis), and undoubtedly several water snakes 

 and other species. All of the snakes are more or less 

 useful in their destruction of rodents and insects, and 

 especially in helping to maintain the general balance 

 of nature so long established as to have become a 

 practical working arrangement of plant and animal 

 life. With the coming of the white man and his domes- 

 ticated animals many of these natural adjustments 

 have been disturbed and some species must be con- 

 trolled through man's efforts. One of these new 

 adjustments seems to require the partial elimination 

 of the poisonous reptiles, and possibly of some of the 

 tree-climbing species that feast on the eggs and young 

 of our native birds, but the harmless snakes need not 

 be destroyed just because they are snakes. At least 

 let us show our intelligence by trying to know their 

 habits and understand their natures before we kill 

 them. 



LIZARDS 



Many species of lizards are seen on hot days along 

 the roadsides, among the desert shrubs, on the rocks, 



