136 



THE SOCIAL LIFE OF ANIMALS 



has been reported for various animals, including 

 rats, (59) chickens (23) and fishes. (118) I shall illus- 

 trate by some of the experiments conducted in our 

 laboratory by Dr. J. C. Welty. These have been 



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125 



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 te. 



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^ 75 



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le 25 

 la 

 <0 



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• GROUPS OF FOUR 

 O ISOLATED 



DAILY FEEDmS 5 



Fig. 24. Many kinds of fishes eat more if several are 

 present than if they are isolated. (From Welty.) 



amply verified by other research workers. In connec- 

 tion with experiments on the effect of numbers on 

 the rate of learning in fishes, which will be discussed 

 later. Dr. Welty undertook to find whether grouped 

 fish ate more or less than if they were isolated. The 

 results of a typical experiment are illustrated in 

 Figure 24. 



Goldfish were photographed to scale, and those of 



