ALASKA. 77 



and energy, to correctly observe and report tbe 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 lur-seals upon iheni. For an estimate 

 based apparently upon good foundations, the following is the 

 phm by which I have been guided : 



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

 every one of tbe former) all arrive upon tbe 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 tbe mark ; now, every female 

 or '•'•cow'^' on its two feet square doubles herself that is, brings 

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

 birth, she visits tbe 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 tbe rookery- 

 grounds without causing the expansion of the same beyond the 

 limits that would be required by tbe adults alo.ue ; 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 sbow about 180,000 

 males, I'emales, and young, on the same area of ground occu- 

 pied previous to tbe birtb of the " pups." 



Xow the males, being treble and quadruple tbe size of the 

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

 same ground, but as they are less than one-fifteenth tbe number 

 of the lemales, they tberefore occupy only one-eigbtb of tbe 

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

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

 virgin females which come on to this breeding-ground for tbe first 

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

 retire, leaving no young to sbow their i)resence on the island. 

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

 late upon two square feet to every aniuial, 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 nuuiber, from one million 

 up to six or seven. 



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

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



