SENSORY ADAPTATIONS OF BATS. 1 85 



Four other bats were used in the same kind of experiments 

 between February 7 and March 6. The details of these experi- 

 ments are, in general, similar to those outlined above. Each of 

 the bats died before the observations were completed. 



Bats numbers 4 and 5 both of which were female Myotis luci- 

 fug2is, were used with a piece of bright carmine-red cloth, four by 

 five inches square, in the cage instead of the smaller piece of white 

 cloth. In the case of bat No. 4 the cage was reversed on the 

 second day, or after the animal had been fed at the cloth only 13 

 times. The association had been quite firmly fixed, however, 

 and the bat went to the back of the cage eight successive times 

 after it had been reversed before it wandered about sufficiently to 

 find the cloth. When it did get to it, it seemed to remember the 

 place and took the cloth in its teeth. It was fed here five times 

 but showed some confusion in finding the place and several times 

 went to the back. The next day it also appeared confused when 

 first placed in the cage and sometimes went to the cloth and 

 sometimes to the back. The following day it seemed to be sick 

 and died two days later. 



Results of the Experiments on Association and the 

 Sense of Direction. 



These experiments show that visual associations are formed 

 slowly or not at all. Sound associations are formed more readily. 

 Tactile associations were not isolated from others but probably 

 enter into the perceptions which lead to finding the cloth as the 

 animals seemed to have the cloth, as well as the location of it, 

 associated with obtaining food. 



The facts relating to the sense of direction will now be taken 

 up. The bats were fed meal worms while they rested on a piece 

 of cloth. The cloth became soaked with the juices of the worms 

 and it also acquired the characteristic odor of the bats to a suffi- 

 cient degree for the human nose to detect it. The bats did not 

 rely upon the sense of smell for finding the place or they would 

 have reached it v/ithout error. 



The room in which the experiments were conducted was not 

 as free from noise as might have been desired. However, it was 

 a basement room with thick walls and there was generally no one 



