1899] THE HABITS OF THE NORTHERN FUR SEAL 29 



water. On its termination the animals swam away in different 

 directions. 



On the 30th June the bull whose harem is numbered II. in the 

 table on p. 25, was observed in coitu twice during the space of about 

 one hour, the first time at about 6.34 p.m. He was afterwards active 

 until about 7.33 p.m., when he again performed the act. 



On the 1st July the same bull was observed in coitu twice during 

 a period of six hours, that is to say, at 12.9 p.m. to 12.14 p.m., and 

 again at 12.33 p.m. until 12.41|- p.m. 



On the 2nd July he was observed in coitu four times during a 

 period of four hours, viz. at 12.35 p.m. until 12.37|- p.m., at 1.30 p.m. 

 until 1.35|- p.m., at 2.5 p.m. until 2.12 p.m. (in the latter case apparently 

 futilely), and at 3.31 p.m. to 3.391 P#M< 



During a period of thirteen hours, in which on various occasions the 

 two bulls were under observation, each was observed in coitu eight 

 times. 



If each bull kept up the same rate during a whole month of 

 twenty-eight days, it is obvious that he could accommodate a harem of 

 over 200 cows. The rate is, however, as shown by the above notes, 

 not constant, and it happened that the periods of greatest activity of 

 the two animals did not always coincide. This I put down to the 

 varied times at which the cows came into heat, and from the notes which 

 I was able to make it seems nearly certain that the cows are covered 

 more than once each. The action of bull 1 during six hours, in 

 which he was observed in coitu no less than six times, led me to 

 believe that, in the case of several at least of the acts which I then 

 observed, it was the same cow which was covered ; but of this I cannot 

 be certain, it being extremely difficult to keep any one cow under obser- 

 vation in a crowded harem. 



On the South rookery of Bering's Island the two bulls are known 

 to have been present from about the 5th July to the 1st August, a 

 period of only about twenty -six days. Their departure at about the 

 latter date may be assumed to have been due to either of two facts — 

 viz. either there were then no females requiring their services, or else 

 their power of accommodating the females was finished for the season. 

 That the latter was the true reason seems almost certain, from the fact 

 that there was a newly-born pup with its mother — probably a three- 

 year-old cow with her first pup — on the rookery beach when I visited 

 it on the 2nd August, and also from the fact that it is in the last week 

 in July or the first week in August that the large old bulls of the 

 Copper Island rookeries leave their harems and retire to the beaches 

 north and south of the breeding-grounds and elsewhere. 



We know that these two bulls at the South rookery had between 

 them a lot of at least 530 cows, or 2 6 5 cows each. If each of these 

 cows were covered only once during the twenty-six days, it would be 

 necessary for each bull to satisfy about ten cows every twenty-four 



