BEAVER LODGES AND BURROWS. 137 



are probably such beavers as, having lost their mates, 

 refused afterward to pair, and led thenceforth solitary 

 lives in burrows. 



Beavers migrate from place to place more or less 

 every season, and particularly when a district becomes 

 overstocked. There is an annual migration down the 

 Missouri River, usually in the month of June, which 

 becomes the more marked from the inability of the 

 migrants ever to find their way back against its power- 

 ful current.^ The Indians affirm that in their local 

 migrations the old beavers go up stream, and the 

 young go down, assigning as a reason that, in the 

 struggle for existence, greater advantages are afforded 

 near the source than lower down upon any stream, 

 wherefore the old beavers wisely appropriate the 

 former. 



For his aquatic life, he needs, as well as possesses, 

 special organic adaptations. He is not only capable 

 of suspending respiration for an interval of several 

 minutes while swimming under water, but also of 

 putting forth, at the same time, his full physical 

 strength. With a relatively small heart and lungs, 

 his respiration is necessarily moderate in amount; but 



in pieces with their forehead, so that in consequence of this office 

 the hair of the head falls out on the right and left side. The 

 merchauts, who are aware of this fact, recognize in the hair of the 

 forehead thus rubbed off the skin of the servant. In the skin of 

 the master this mark of recognition is wanting, as he employs 

 himself with catching fish." — (Brandt, Memoires de I'Academie 

 de S. Petersbourg, tome vii. 349.) 



^ A trapper whom I met on the Missouri River, in 1862, below 

 Fort Piere, in Nebraska, informed me that the beavers were then 

 (May 27) coming down the river ; that he saw them daily, and 

 had taken over fifty. 



