ALASKA. 77 



and energy, to correctly observe and report the area and posi- 

 tion of the rookeries year by year. 



With a knowledge of the superficial area of these breeding- 

 grounds, the way is opened to a very interesting calculation 

 as to the number of the fur-seals upon them. For an estimate 

 based apparently upon good foundations, the following is the 

 plan by which I have been guided : 



When the adult males and females (fifteen of the latter to 

 every one of the former) all arrive upon ^the rookery, I think a 

 space a little less than two feet square to each female is a large 

 one for that required by each' animal, in obedience to its habit, 

 and may safely be said to be under the mark ; now, every female 

 or '■^cow''' on its two feet square doubles herself, that is, &rmrjfs 

 forth her young, and in a few days, or about a week after its 

 birth, she visits the water, and is not one-quarter of the time 

 on land again during the season. In this way it is clear that 

 the female seals almost double their number on the rookery- 

 grounds without causing the expansion of the same beyond the 

 limits that would be required by the adults alone ; for every 

 100,000 breeding-seals will be found to consist of more than 

 85,000 females and less than 15,000 males, and in a few weeks 

 after the landing of the females, they will show about 180,000 

 males, females, and young, on the same area of ground occu- 

 pied previous to the birth of the " pups." 



Now the males, being treble and quadruple the size of the 

 females, require about four feet square for their use on this 

 same ground, but as they are less than one-flfteenth the number 

 of the females, they therefore occupy only one-eighth of the 

 breeding-ground of the 100,000 supposed, and this surplus area 

 of the males is more than balanced by the 15,000 to 20,000 

 virgin females which come on to this breeding-groundforthe first 

 time to meet the males ; they come, rest a few days or a week, and 

 retire, leaving no young to show their presence on the island. 

 Taking all these points into consideration, I quite safely calcu- 

 late upon two square feet to every animal, big and little, on the 

 breeding-grounds. Without following this system of computa- 

 tion, a person may look over these swarming myriads of seals, 

 guessing vaguely and wildly at any number, from one million 

 up to six or seven. 



Below are the figures made from my survey of the area and 

 position of the breeding-grounds of the fur-seal on Saint Paul's 



