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 opening 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 animal but a tool-making animal.
As Yerkes remarks, “Sharper contrast it would be difficult 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
[ 302 ]
