MAMMALS OF THE REGION 111 



floor, where they can barely be seen by a powerful 

 searchlight, and are entirely out of reach of ladders, 

 so the estimates of numbers must be based on their 

 flights to and from the cave. On my arrival at the 

 cave, March 11, they were quiet, and most of them 

 apparently were still in the torpor of hibernation. A 

 few days later, on warm evenings, they began to come 

 out of the west entrance in considerable numbers and 

 disappeared in the darkness of the night. At first 

 about one thousand were estimated as leaving the cave 

 during the twilight hour, but later the numbers in- 

 creased until on May 5 about twelve thousand (partly 

 counted and partly estimated) came out in one hour, 

 from 7:10to8:10p.m., mountain time. The following 

 morning they reentered the cave before daylight, at 

 4:00 to 4:45 a.m., or up to twenty-five minutes before 

 sunrise. Each morning they returned and entered the 

 cave apparently in considerably less numbers than 

 those leaving the night before. Undoubtedly many 

 scattered out at this season over the low country, where 

 insect life had become abundant, and where comfortable 

 shelter could be found near the source of food supply. 

 All evidence points to the fact that the Carlsbad 

 Cavern is mainly a wintering place for these bats, where 

 they pass the winter in a state of torpor. 



In late summer and early fall the bats are said to 

 gather at the cave in enormous numbers. For several 

 hours in the evening they pour from the openings in 

 black streams so dense that they can be seen from a 

 distance of two miles, and fill the shafts so closely that 

 they can be caught in the hands as they pass out. 



