CHAPTER V 



THE BEAVER AS A SPECIES 



Castor canadensis and Castor fiber. 



OF the order rodentia the beaver is the second in 

 point of size, the only species exceeding it being 

 the Capibara (Hydrochoerus capivars) of South 

 America. The American and European beaver 

 constitute the only living representatives of the 

 genus castor, and the difference between the two 

 is so very slight as to be scarcely noticeable to any- 

 one but a scientist. Externally, except in point of 

 size, the two species are practically identical, the 

 American being slightly larger, but an examination 

 of the skulls shows certain minor differences, chief 

 of which is the slightly greater proportional length 

 of the nasal bones and narrower skull of the 

 European species (Castor fiber). Another less 

 noticeable mark of distinction is that the castoreum 

 obtained from the European species, especially 

 those from Russia, is more valuable and contains a 

 greater proportion of castorin resin and albumen. 

 In point of age the beaver is evidently an animal of 

 great antiquity, not only in its present form but 

 the larger and extinct Trogontherium (of Europe) 

 and the Castoroides (of America), neither of which 



