WHAT DO ANIMALS KNOW? 



inherited knowledge, the amount left, representing 

 its own power of thought, would be very small. Dar- 

 win tells of a pike in an aquarium separated by 

 plate-glass from fish which were its proper food, and 

 that the pike, in trying to capture the fish, would 

 often dash with such violence against the glass as to 

 be completely stunned. This the pike did for three 

 months before it learned caution. After the glass 

 was removed, the pike would not attack those par- 

 ticular fishes, but would devour others that were in- 

 troduced. It did not yet understand the situation, 

 but merely associated the punishment it had received 

 with a particular kind of fish. 



During the mating season the males of some of 

 our birds may often be seen dashing themselves 

 against a window, and pecking and fluttering against 

 the pane for hours at a time, day after day. They 

 take their own images reflected in the glass to be 

 rival birds, and are bent upon demolishing them. 

 They never comprehend the mystery of the glass, be- 

 cause glass is not found in nature, and neither they 

 nor their ancestors have had any experience with it. 



Contrast these incidents with those which Dar- 

 win relates of the American monkeys. When the 

 monkeys had cut themselves once with any sharp 

 tool, they would not touch it again, or else would 

 handle it with the greatest caution. They evinced 

 the simpler forms of reason, of which monkeys are 

 no doubt capable. 



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