SENSORY ADAPTATIONS OF BATS. I41 



animals happen to come out at the right time. For this purpose 

 daily observations were made on the number, location and move- 

 ments of bats in the large room (Fig. i, 2) near the Shawnee 

 Cave entrance and also near the entrance of the Twin Cave (Fig. i , 

 5), throughout the year, excepting at several times when the 

 cave stream was too high to permit access to these places. The 

 large chamber half way between the Shawnee and Twin Cave 

 entrances was visited weekly during most of the year. 



Since this work was begun I have visited one or more times 

 about fifteen other caves, ranging in size from unnamed sinkholes 

 to caverns as large as Marengo and Wyandotte in Indiana and 

 Horse and Mammoth Caves in Kentucky. All of them were 

 inhabited by bats, and in all the approximate number and distribu- 

 tion of these animals have been noted, together with such obser- 

 vations on their habits as it was possible to make. Live bats 

 have also been under observation in the laboratory from time to 

 time. 



Bats have resting places but no homes. They never construct 

 any sort of a nest or den nor do they habitually return to a fixed 

 spot at regular intervals, although individuals may have a tend- 

 ency to resort frequently to the same place. Stone and Cram 

 ('02) state that they appear to hang themselves up wherever day- 

 light finds them. These authors give data which indicate that 

 there may be a periodic return to the same spot at short but 

 irregular intervals. 



Of the species found in eastern North Ameria some are habit- 

 ually cave dwellers and some tree dwellers. The habits of the 

 two groups overlap, however, and at least two of the tree-inhabit- 

 ing species, Lasiiinis cincrciis and L. borealis are known to have 

 entered caves in the past. 



I have not been able to obtain a reliable record of either of 

 these species living in the caves of the Mississippi valley at the 

 present time. In the large room (Fig. 1,4) of the Shawnee 

 Cave more than two hundred skulls of L. borealis and two of L. 

 cinereits wcvQ. found scattered among the rocks on the floor of the 

 chamber. Careful searching in the same and other places failed to 

 discover the remains of more than twenty-five individuals of the 

 three species now most abundant there. The skulls, accompanied 



