REPORT OF AMERICAN COMMISSIONERS. 351 



convinced us that at least there could be no Testimony as to 



no luck of males. 



deficiency and that it was a practical impossi- 

 bility for any breeding cow to escape service 

 on account of paucity of virile males. 



The unavoidable conclusion is, then, that the Decrease caused 



by killing females. 



deterioration of the herd must be attributed to 



the destruction of female seals. 



If a herd of seals be taken in its natural con- Natural condi- 

 tion of kerd. 

 dition, that is, as not interfered with by man, 



males and females will be found practically equal 

 in number, as the number of births in a year of 

 both sexes is the same, and we have no reason 

 to believe there is any great difference in the 

 natural mortality of the sexes. The total num- 

 ber of females may be divided into two classes, Classes of fe- 



'' ^ males. 



the breeding and the nonbreeding, the former 

 being probably a large proportion of the whole. 

 The nonbreeding females include those that have 

 not yet reached the reproductive age and the few 

 which from old age or other causes are barren. 



The male seals may likewise be divided into classes of males. 

 two classes, the virile and the nonvirile, the lat- 

 ter including those below the age of virility and 

 those impotent on account of old age. The 

 reproductive power of the herd, therefore, lies in 

 the breeding females and the virile males. The 

 maintenance of the birthrate, the vital and essen- On what birth- 



. , , , , . rate depends. 



tiai element in the preservation and perpetuation 



