190 WALTER LOUIS HAHN. 



They have no nests, dens or fixed homes. The species studied 

 stay in the caves during the greater part of their existence. 

 They usually go in far enough to be in a constant temperature 

 and total darkness but do not select their resting places with 

 reference to the size of the cave, the nature of the opening or the 

 amount of moisture. 



They have few enemies. Consequently fear is but little de- 

 veloped. 



About five sixths of a bat's entire existence is spent in a dor- 

 mant condition. This condition is not dependent upon tempera- 

 ture or season but upon the condition of metabolism ; a large 

 amount of fat is favorable to torpor. 



In the caves, where conditions of light and temperature are 

 constant, bats come to the cave entrance at irregular intervals. 

 The length of time between these intervals depends upon the 

 amount of surplus fat stored in the body. 



They leave the cave only when favorable conditions of light 

 and temperature prevail, and go back to the interior of the cave 

 if the light is too intense or the air too cold. 



Food consists of insects that are caught on the wing. 



Several senses aid in its perception. Smell and taste are 01 

 no use for this purpose. Sight may aid to some extent. Hear- 

 ing and the tactile sense are chiefly relied on to perceive and 

 locate food. 



Bats are more helpless on their feet than most birds. In the 

 air they have greater agility. 



They can check their momentum very quickly. In flight, they 

 can secure hold of a surface, only slightly rough, with a single 

 thumb or with one foot. 



The breeding habits of our species are not well known. They 

 mate in the fall and the young are born early in the summer. 

 Breeding females leave the caves during the period of gestation 

 and rearing the young. 



The sexes do not segregate while they remain in the cave. 



Bats in captivity do not readily learn to pick up food from the 

 floor of the cage. They will eat food presented to their mouths 

 and will go to a dish for water. 



They do not live well in captivity except when in the quies- 

 cent state. 



