ANIMAL PSYCHOLOGY. 263 



processes undistinguishable from similar processes of 

 reasoning performed by the human mind. 



Again, the construction of a canal from the pond 

 across the lowlands to the rising ground, upon which 

 the hard wood is found, to provide a way for the 

 transportation of this wood by water, is another re- 

 markable act of animal intelligence. A canal is not 

 absolutely necessary to beavers any more than such a 

 work is to mankind; but it comes to both alike as the 

 result of progress in knowledge. A beaver canal 

 could only be conceived by a lengthy and even com- 

 plicated process of reasoning. After the conception 

 had been developed and executed in one place, the 

 selection of a line for a canal in another would in- 

 volve several distinct considerations, such as the 

 character of the ground to be excavated, its surface, 

 elevation above the level of the pond, and the supply 

 of hard wood near its necessary terminus. These, 

 together with many other elements of fitness, must 

 be ascertained to concur before the work could be 

 safely entered upon. When a comparison of a large 

 number of these beaver canals has demonstrated that 

 they were skillfully and judiciously located, the in- 

 ference seems to be unavoidable that the advantages 

 named were previously ascertained. This would re- 

 quire an exercise of reason in the ordinary accepta- 

 tion of the term. 



And this leads to another suggestion. Upon the 

 Upper Missouri these canals are impossible, from the 

 height of the river banks; and besides this they are 

 unnecessary, as the cotton-wood, which is the prevail- 

 ing tree, is found to the edge of the river. While, 

 therefore, canals are unknown to the Missouri beavers, 



