154 WALTER LOUIS HAHN. 



attempt to recover it and does not even turn its head to look for 

 the lost morsel ; generations of flying ancestors have not found 

 it advantageous to try to recover an object dropped while on the 

 wing. 



Bats are not wholly dependent on a single sense for distinguish- 

 ing their food. Smell, on which many other mammals are chiefly 

 dependent, here is of subordinate importance. The reason is to 

 be found in the way in which food is secured. Any creature 

 walking on a solid surface and having a characteristic odor, can 

 be located, or can be traced some time later, by an animal with a 

 keen sense of smell. But flying insects, which form the chief 

 food of bats, do not leave a permanent odor in their path nor 

 can their presence be definitely localized because the odors are 

 diffused too rapidly and unevenly by shifting currents of air. I 

 have held meat, meal worms and insects near a hungry bat and 

 it did not seem to notice their presence until some sense besides 

 smell was stimulated. However, fresh meat fastened to the side 

 of the cage was found and eaten after a time. On one occasion 

 a bat that was running across the floor of a cage perceived a piece 

 of meal worm it was passing and picked it up. This was, how- 

 ever, the only instance of the sort I have observed in handling 

 and feeding a large number of bats. The same animal and others 

 seemed (juite unable to find meal worms or insects lying quietly on 

 the bottom of the cage. Occasionally they found meat placed 

 in a small dish. This happened more often with Eptcsicus and 

 Fipistrcllus than with either species of Myotis, though the latter 

 found the meat more readily when it was fastened to the side of 

 the cage so that the animals climbed about over it. 



It must not be inferred from the above statements that the 

 sense of smell is lacking, or even rudimentary. All bats have a 

 strong odor, the purpose of which is probably to attract others 

 of their kind. This may be taken as an indication that smell is 

 well developed, for otherwise the odor would be useless. The 

 action of the animal mentioned above in stopping to pick up the 

 meal worm, and the ease with which others learned to find and 

 eat such unfamiliar food as meat, also indicate that the sense 

 of smell is not lacking. The fact that they do not usually notice 

 food when it could be perceived by this sense alone, indicates 

 only that they are not accustomed to find it in that way. 



