Twilight in the South 331 



all of them retire to the Ross Sea or other such retreat which we 

 have found — both the whales and the whaling industry are probably 

 doomed. If, on the other hand, either a sufficient breeding stock is 

 left behind, or they have other inaccessible retreats where they can 

 multiply unmolested, we may expect to be able to go on slaughter- 

 ing whales forever, just as we have the worthy cow for several 

 thousand years, and still have more available at the end of the process 

 than we had at the beginning. 



There is, however, one other factor that works in favor of the 

 whales. This is a rather hard thing for those who are not specifically 

 interested in biological matters to comprehend. It is even hard for 

 those who are, unless they have had specific ecological experience 

 in the field rather than in mere theory. 



Just as there is a thing called "population pressure," the meaning 

 of which should be obvious to everybody, there is also a very potent 

 corollary force at work in nature which can be called "spatial ten- 

 sion." This means, that in order to keep life on this planet going, not 

 only must a balance be preserved among all its parts, but an over-all 

 "fullness" must be maintained just as if the whole habitable envelope 

 of the earth were a vast sponge that had to be kept saturated; as the 

 cliche has it: "Nature abhors a vacuum." Thus, if you clean all the 

 whales out of a sea, others will come in from adjacent areas where 

 there is a surplus, or some other creatures will fill the niche previ- 

 ously occupied. Furthermore, each of nature's niches has a specific 

 volume, meaning that if you eliminate a hundred whales, aggregating 

 "x" cubic feet of flesh, from any one area, there will be space for, 

 say, a hundred million small fish which together add up to "x" cubic 

 feet. If small fish are not available, large turtles, medium-sized sharks, 

 countless shoals of tiny shrimps, or some other animal that can fill 

 that particular niche will do just as well. The important point is that 

 the greater the vacuum, the more urgently nature seems to adver- 

 tise for new tenants. Moreover, nature is very direct in her actions, 

 is a past master at cutting corners, and apparently has an unlimited 

 number of tricks up her allegorical sleeve. One of her neatest ways 

 of refilling a vacuum is to step up the breeding rates of the animals 

 that have survived the persecution or catastrophe causing the reduc- 

 tion in their numbers. 



Thus, provided we are sure there is a safe basic breeding stock of 



