138 THE AMERICAN BEAVER. 



as the blood must circulate while respiration is sus- 

 pended, other and independent vessels are provided 

 near the heart for its reception, where it accumulates 

 until respiration is resumed. If this blood were thrown 

 upon the lungs while their functions were suspended, 

 it would produce suffocation. It is said that he will 

 swim a quarter of a mile under water without coming 

 to the surface. Trappers differ as to the time he will 

 remain under water, but agree in placing it between 

 five and ten minutes. Mr. Atchinson, a Lake Superior 

 trapper, informed me that he once held a beaver, 

 caught in a trap, under water for the full space of ten 

 minutes, as he believed, without extinguishing life. 

 In the winter they are often compelled to swim fifty 

 and a hundred rods under the ice to find open water; 

 and they have been seen to take in a fresh cutting, 

 through a hole in the ice, and swim with it for thirty 

 rods to their lodge. 



The musk-rat, whose aquatic habits, and use of 

 the pond, the burrow, and the lodge, affiliate hiin 

 with the beaver, resorts to a singular but well- 

 attested expedient to lengthen the period of sus- 

 pended respiration, which may be mentioned in this 

 connection. When swimming under ice he comes up 

 to its lower surface, and, having expelled the air from 

 his lungs, waits for a moment, and then, after drawing 

 in again the bubbles of air, proceeds on his way. 

 This fact has been confirmed to me by so many dif- 

 ferent observers, that I see no reason to disbelieve its 

 truth. Whether the air, by its contact with the ice, 

 recovered some property of which it had become ex- 

 hausted, I leave as a question to those capable of its 

 determination. It is claimed that the beaver resorts 



