HEREDITY OF WILDNESS AND SAVAGENESS IN MICE 65 



The quality of the tone resembled somewhat that of a fife 

 or flute, but each tone ended with a slight throaty click. The 

 tones were uttered at the rate of four or five per second in 

 groups of varying size. Sometimes a group occupied one 

 second, sometimes as long as ten seconds. As a rule, the tones 

 of a group were not clear and distinct but, instead, were uttered 

 so rapidly as to seem connected. The throaty click was more 

 noticeable in the case of the last tone of a group. Often the 

 "singing" would be continued for a period of ten or fifteen 

 minutes with rests between groups. 



The sound could readily be heard at a distance of fifteen or 

 twenty feet, but it was difficult to localize it. The individual 

 "sang" little during June, 1912, and it was not heard after 

 July 1st, 1912. She died in August, apparently of old age. 



During May, 1912, "singing" was again heard in the room 

 in which the "singing" mice had earlier been captured, but 

 efforts to capture the "singer" failed. 



In January, 1913, a "singing" mouse was captured in the 

 home of an Italian family in Brooklyn, New York. It was 

 brought to the Laboratory and appears in the study described 

 in this paper as female no. 475. There was captured with it 

 a male, mouse no. 474, which, however, did not "sing." These 

 two mice were mated and produced six of the wild individuals 

 which were raised and tested and later used as breeders in 

 Series B of the study in wildness and savageness inheritance. 

 This "singer" was mated with a tame male, and again with a 

 F2 hybrid male but no "singer" appeared in these two litters, 

 nor among the first, second, or third generation hybrids from 

 the six wild offspring mated with tame individuals. 



Later another "singer" was found on a farm in Michigan. 

 It was sent to the Laboratory and proved to be a female also. 

 No attempt was made at breeding this individual since it 

 arrived just before the end of the study and there would not 

 have been sufficient time for any observations to be made on 

 the offspring. 



The "singing" of these last two individuals was very much 

 like that of the first, except that the mouse from Michigan 

 did not "sing" as long at any time nor as frequently as did the 

 other two. 



The writer received several letters from different persons 

 in various parts of the United States giving their observations 



