BATS 63 



1. As may be gathered from their small size, the eyes of the bat 

 are not sharp-sighted. (Compare, on the other hand, the eyes of the 

 owl.) 



2. The sense of touch, on the other hand, is developed to a degree 

 almost inconceivable to human beings. Thus, bats whose eyes had 

 been covered with sticking-plaster, and who were then let loose in a 

 room in which a large number of threads were extended, never once 

 ■collided with the latter. This can only be explained by assuming that 

 the animals are sensible to the vibrations of the air generated by the 

 stroke of their flying membranes and reflected by surrounding objects. 

 'The fineness of the threads in the above experiment itself shows how 

 faint such vibrations must be. In the same way the animal becomes 

 sensible of the faint air vibrations generated by a flying insect. It feels its 

 prey, as it were, from afar. This extremely fine sense of touch has its 

 seat in the flying membrane, in the delicate pinnae of the ears, and the 



Skull of a Bat. (Magnified live times. ) 



■covers placed in front of the external auditory aperture. The existence 

 •of this sense also renders intelligible the unusual size of the external ears 

 and the absence of the thick coating of fur from them as well as from 

 the flying membrane. 



3. The sense of hearing is equally acute, as is, indeed, shown by the 

 voice of the animal, which is so fine and high-pitched that many people 

 are unable to perceive it at all. The creature, on the other hand, must 

 be able to hear tones of this kind. (Why ?) The large pinnae, which are 

 movable and capable of being laid back, in fact, represent ear-trumpets. 

 At the commencement of the aerial voyage they are erected, and probably 

 enable the animal to hear sounds inaudible to human ears, such as the 

 flight of a moth, more especially as the animal itself moves without 

 sound. (Compare with cat and owl.) Animals endowed with a fine 

 sense of hearing cannot tolerate loud tones or noises. (Compare the 

 dog.) Hence, according to some naturalists, the ear-covers of the bat, 

 by closing the auditory passage, save the animal from being annoyed or 

 iormented by sounds or noises of this description. 



