DWELLINGS lt>Al 



table. From time to time the beavers remove the 

 bark of the fallen trees and feed on it. 



Mr. Lewis H. Morgan studied the American bea- 

 ver with great care and thoroughness, more espe- 

 cially on the southwest shore of Lake Superior; he 

 devotes fifty pages to the dams, and it is worth while 

 to quote his preliminary remarks regarding them: 

 u The dam is the principal structure of the beaver. 

 It is also the most important of his erections, as it is 

 the most extensive, and because its production and 

 preservation could only be accomplished by patient 

 and long-continued labor. In point of time, also, it 

 precedes the lodge, since the floor of the latter and 

 the entrances to its chamber are constructed with 

 reference to the level of the water in the pond. The 

 object of the dam is the formation of an artificial 

 pond, the principal use of which is the refuge it 

 affords to them when assailed, and the water-con- 

 nection it gives to their lodges and to their burrows 

 in the banks. Hence, as the level of the pond must, 

 in all cases, rise from one to two feet above these 

 entrances for the protection of the animal from pur- 

 suit and capture, the surface-level of the pond must, 

 to a greater or less extent, be subject to their imme- 

 diate control. As the dam is not an absolute neces- 

 sity to the beaver for the maintenance of his life, his 

 normal habitation being rather natural ponds and 

 rivers, and burrows in their banks, it is in itself con- 

 sidered a remarkable fact that he should have vol- 

 untarily transferred himself, by means of dams and 

 ponds of his own construction, from a natural to an 

 artificial mode of life. 



