32 DENIZENS OF THE DESERT 



with hundreds of stones in it the size of pullet's 

 eggs. It seems quite evident that they could 

 not have been carried in the small mouth, and 

 how could the neotoma carry them in her paws! 

 A mystery equally hard to solve is found 

 among the desert .species that surround their 

 nests with the joints of the Bigelow's cholla 

 cactus. This species of shrublike cactus, or 

 Opuntia, has needles so close-set, so impene- 

 trable, and so formidable that it seems no 

 creature could carry the joints in any way, 

 much less let go of them once it had them in 

 its grasp. With the least touch they penetrate 

 the toughest-hided animals and hang on with a 

 tenacity that is most pronounced. Only those 

 who have ever tried to pick up or even touch 

 one of the joints of the Bigelow's cholla know 

 how terrible and how painful the prick of the 

 needles is. Not without good reason the Indi- 

 ans declare that the joints of this cactus jump 

 at you as you come near. The wood rat is the 

 only creature I know of that does not fear to 

 handle them. When we remember that these 

 joints are larger or almost equal in size to her 

 own tender body and that they are given to 



