CREATION BY EVOLUTION 



nut, which he then draws toward him by pulling in the 

 shawl." 



Kohler's Sultan, who had learned to use a stick to draw 

 in bananas that were placed beyond the bars of his cage, 

 was given two hollow pieces of bamboo, one of which would 

 fit into the other. Food was placed outside his cage beyond 

 the reach of a single stick. At first Sultan would use one 

 stick to poke the other one nearer the food. These efforts 

 of course proved to be fruitless. After this, according to 

 his keeper, ''Sultan first of all squats indifferently on the 

 box, which has been left standing a little back from the 

 railings; then he gets up, picks up the two sticks, sits down 

 again on the box and plays carelessly with them. While 

 doing this, it happens that he finds himself holding one rod 

 in either hand in such a way that they lie in a straight line 

 (Fig. 3) ; he pushes the thinner one a little way into the open- 

 ing of the thicker, jumps up and is already on the run toward 

 the railings, to which he has up to now half turned his back, 

 and begins to draw a banana toward him with the double 

 stick." 



Sultan did not try to join two large pieces of bamboo 

 together, but he sometimes tried to chew off a part of the 

 end of a piece of wood that was too large to enter the hollow 

 of a piece of bamboo and by forcing the pieces of wood and 

 bamboo together made a jointed stick that he could use. To 

 a certain extent, then, Sultan was not only a tool-using ani- 

 mal but a tool-making animal. 



As Yerkes remarks, "Sharper contrast it would be diffi- 

 cult to imagine than that between the relatively blind and 

 seemingly purposeless trial-and-error effort that has been 

 described by Thorndike as typical for the cat when it faces 

 novel problems and the definitely directed and apparently 

 thoughtful behavior of the chimpanzee. The great apes 



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