70 ANIMAL LIFE OF CARLSBAD CAVERN 



How they find their way about or locate their food in 

 the utter darkness is still a cave mystery. Their eyes 

 appear normal, and they can see well when brought 

 out to the light, although many of those born and 

 raised in the far rooms could never have seen a ray of 

 light before. They are no different in color from those 

 living outside, a dull buffy gray above and white below. 

 Occasionally one running over the floor of the cavern 

 was seen by lantern light, but most of those taken were 

 caught in traps set along the runways and baited with 

 rolled oats. More were caught in the daytime than at 

 night, but probably there is no difference in the periods 

 of their activity unless in the first large rooms where a 

 faint trace of light from the openings would make it 

 possible for them to see during the daylight hours. 

 That they are permanent residents of the cave is shown 

 by the fact that most of the females caught were nurs- 

 ing young or contained three to six embryos. Most of 

 those caught in March and April were adults, for the 

 young were not yet large enough to run about or get 

 into traps. Those taken were larger and fatter than 

 the same species caught outside, evidently as a direct 

 result of comfortable climate and abundant food. 



The stomachs of those taken for specimens were 

 filled with remains of cave crickets, in addition to re- 

 mains of tourists ' lunches and rolled oats used for trap 

 bait. The crickets, which are abundant throughout 

 the cave, seem to be their main and only permanent 

 source of food supply. 



The cave mouse with medium long tail differs from 

 the eastern white-footed mouse mainly in slightly paler 

 gray brown color. 



