210 COUNTER-CASE OF GREAT BRITAIN. 



United States Ingeiiious and elaborate diagrams accompanying the 

 aae, pp. - • jjgpj^^.j^ Qf ^|^p United States Commissioners, are intended 

 to demonstrate in wliat way a large proportion of yonng 

 male seals may be annually killed without detriuient to the 

 general reproductive powers of the fur-seals collectively. 

 These diagrams may be accepted as an elaboration and 

 explanation of the theory in accordance with which the 

 killing of seals upon the Pribyloff Islands has heretofore 

 progressed, but are very far from proving the expediency 

 of such killing. They are based entirely on assumed data, 

 for it is not possible, as in the case of domestic animals, to 

 obtain any facts resjjecting many of even the more im])or- 

 tant points connected with the history of the fur-seal. Not 

 onlj^ are the data respecting the life history of the fur seal 

 thus assumed, but the prepotent effects of natural causes, 

 climatic and other, are necessarily omitted from considera- 

 tion in the calculations presented. 



The fundamental assumption of the intricate com- 

 242 ])utations upon which these diagrams are based is 

 found to be that, in consequence of the polyga- 

 mous habit of the fur-seal, a large proj^rtion of males 

 may be killed each year without detriment, if only the 

 females be spared. The fallacy of this proposition as 

 applied to wild animals, in respect to which the selection 

 of breeding males bj^ man is not possible, has already been 

 c^r,p!ie3^***^'* pointed out. If, in effect, any selection is i)raf'tised in kill- 

 ing upon the islands, it is the finest males which are chosen 

 for killing, thus broadly reversing the operations of nature. 



Bitt this is only the first of numerous succeeding assump- 

 tions upon which the whole calculation is built up, errors in 

 any one of which must materially alter the results arrived 

 at; and, in consequence of the uncertainty attaching to all 

 of them, the diagrams presented cannot be considered as 

 possessing any practical value. 



It is stated that — 



Ibid., p. 352. unfortnnately, we have no "Tables of Mortality" for seals; we know 

 ouly approximately tbeir inaximuiu age, aud have little knowledge 

 as to the distribution of their death-rate. 



This, however, does not deter the computer from assum- 

 ing the normal life at twenty years, from assuming that 

 one-half the young born, die within the first year after 

 birth, or from assuming an ''approximate" death rate for 

 the already assumed further years of normal life of the 

 seal. It is then still further assumed that the number of 

 males and fenuiles born is equal; and though this ])artic- 

 ular assumption appears to be a probable one fi^om analogy 

 ■with other animals, no satisfactory evidence is forthcoming 

 in the case in question. 



The number of years during which the female may re- 

 main fertile, or the male may retain his virility, are like- 

 wise quite unknown. Experience gained in the case of 

 sheep, and that also resulting from the keei)ing of deer in 

 parks and under observation, shows that, though polyga- 

 mous, the males of these animals are unable to maintain 

 their virility unimpaired (in conseq^uence of the demands 



