SENSORY ADAPTATIONS OF BATS. I9I 



Experimental studies show that neither sight nor the external 

 ears and tragi are necessary for the perception of obstacles dur- 

 ing flight. 



The body hairs probably have a sensory function. 



Obstacles are perceived chiefly through sense organs located 

 in the internal ear. 



Perception is probably due to the condensation of the atmos- 

 phere between the moving animal and the object it is approaching. 



Bats show a remarkable ability to return to a particular spot 

 for food or for the purpose of escaping from an enclosure. 



It is difficult to explain how they find their way by means of 

 the five senses famihar to us. 



The presence of a sixth sense, that of direction, will explain 

 all of the facts. 



It has not been conclusively shown that such a sense exists. 

 If it exists in any animals we should expect to find it in bats. 

 Their habits are such that a sense of direction would be of ad- 

 vantage to them in the struggle for existence. 



