FUR-SEAL CENSUS, PRIBILOF ISLANDS, 1917,. 



107 



Tlie next table, which shows percentages of gains of these classes, 

 is very instinctive. Thus harem bulls increased 38.57 per cent from 

 1916, while the idle bulls only increased 2.81 per cent. This in the 

 presence of an enormous number of adult males out on the hauling 

 grounds seems to be conclusive proof that when a bull can not get 

 within about three places of a mass of cows he gives up and quits 

 trying. If this proves true in succeeding years it means that the 

 percentage of idle bulls to harem bulls will not normally be far from 

 50 when these classes exist in sufficient abundance to maintain the 

 minimum average harem. The fact that this percentage went to 

 75 in 1916 and that the average harem was 33 (not the minimum as 

 then suspected) means nothing more than that the idle bulls as a class 

 were young and not able to secm'e cows from the stronger harem 

 masters. If the average harem in 1916 had been at a minimum and 

 the percentage of idle bulls 75, while in 1917 the harem had remained 

 minimum, but idle bulls dropped to 55.7 per cent, it would be very 

 suggestive that there were fewer bulls in the latter year. But since 

 this is known absolutely not to have been the case, the explanation 

 on the basis that the idle bull ceases to be one if he can not get within 

 a certain distance of the cows seems justifiable. 



In the light of this recently acquired knowledge, it would seem to 

 have been permissible to have classed a portion of this 75 per cent of 

 idle bulls in 1916 as young bulls. But since this is an indefinite divi- 

 sion at best, it is believed it might have proved misleading. 



Comparison of Harem and Idle Bulls in 1917 with 1916. 



oLoss. 



