302 DISCOVERY REPORTS 



the mother bellowing at intervals in the same way as do cows when they come ashore ; 

 finally the pup began to suck and the cow appeared satisfied. 



As more and more of the cows are served and take to the water the pups begin to 

 herd together in "pods" and spend their time playing together and sleeping (Plate IV, 

 fig. 2). They begin to play at the edge of the water or in pools left by the tide and may 

 be very much scattered at low water ; but they return before the rising tide and seldom 

 venture into deep water before the cows lead them out to it. The sea lion pup is a 

 clumsy and excitable swimmer and cannot dive eflfectively : the eflPorts of the cow appear 

 to be specially directed towards teaching the pup to dive, that is, to swim downwards. 

 The pup is gradually coaxed from the beach by the cow calling and then swimming 

 away, but she will come back again and again even to the water's edge, if the pup 

 persists in returning to the shore. When the two are finally in deep water the mother 

 begins to play about, diving and swimming idly round while the pup endeavours to 

 follow her. It is a belief in the Falklands that the cow takes the pup on her back and 

 thus teaches it to dive. What happens is the reverse, the pup tries to climb out of the 

 water on to the mother's back and she is intent on diving away from under it so as to 

 force it to swim by itself and eventually to follow her downwards. 



By March there is a complete coalescence of the herd and a general restlessness 

 sets in. Individual cows may be seen wandering along the beach accompanied by their 

 pups, and I have seen a well-defined group of about five hundred sea lions move itself 

 bodily along the beach for a distance of half a mile or so, for no apparent reason 

 unless it were to find more shelter from the sea: the new site, having been empty 

 for some time, must have been a good deal more sanitary than the previous one. Apart 

 from these purely local movements the animals leave their rookeries and the diminu- 

 tion, although gradual, is steady, as is shown by the counts on Cape Dolphin rookery. 



SEXUAL CAPACITY OF BULLS 



From the economic standpoint the sexual capacity of the bulls is a matter of great 

 importance, since on it depends the proportion of bulls which may be killed : an attempt 

 has therefore been made to arrive at a reasonable figure. For a variety of reasons it was 

 not always possible to distinguish between the classes of sea lion in the count of the whole 

 herd, but a count of animals was made in which distinctions were recorded. Care was 

 taken to distinguish between bulls which had one cow and those which had more than one. 



The total number counted was 2298, comprising 1984 cows and 314 bulls, an average 

 of 6-3 cows per bull. Of the 314 bulls 69 had one cow each, and after deducting them 

 and their cows from the totals, we have 1915 cows and 245 bulls, with the increased 

 average of 7-8 cows per bull. In the following calculations on the sexual capacity of 

 the bulls those with but one cow are omitted, since they cannot properly be regarded 

 as harem bulls, but rather as idle bulls which have succeeded in securing single stray 

 cows ; they are generally found on the outskirts of the rookeries or even apart from 

 them altogether and, as is stated on p. 307, the menage is often broken up and the bull 

 reverts to his status of idle bull. 



