122 Chapter III. 



by Friedrich in a recent publication.^ The beaver- 

 lodge is nothing but an accumulation of brushwood 

 above the opening of the underground chamber, which 

 is the real center of the whole dwelling. Wherever 

 beavers are living in colonies and when circumstances 

 favor the full development of their instinctive skill in 

 building, they construct their well-known dikes- to 

 dam the water, and sometimes they even build canals 

 for the transportation of timber. Although these 

 works are the result of the co-operation of several 

 families, yet each pair works only for its own pur- 

 poses ; there is never any division of labor like that 

 in ant colonies. Of course, observers like Lewis H. 

 Morgan,^ who mistake for intelligence every action 

 due to sensitive cognition, discover many proofs of 

 high intelligence in the doings of the American 

 beavers. However, this so-called "free intelligence" is 

 nothing else than the power of adapting their buildings 

 to the changes of situation. This power is possessed 

 also by ants in at least an equal degree. If Morgan 

 and Romanes,* e. g., regard it as an infallible proof 

 of the intelligence of beavers that they regulate the 

 level of their ponds by widening or narrowing "the 

 orifices of their dams as the case may be," they should 

 admit the same in ants, which regulate the degrees o£ 

 moisture and temperature of their nests by changing 



1) "Die Liber an der mittlern Elbe" (Dessau, 1894), p. 20 ff. 



2) According to Friedrich they also occur at some places on the 

 banks of the middle Elbe, although indeed on a smaller scale; there- 

 fore they are due to an instinct common both to the European and 

 the American beaver. 



8) "Tlie American Beaver and his Works" (Lippincott & Co., 

 1868). 



*) "Animal Intelligence" (6th ed), p. 377 ff. 



