the Sperm Whale {Physeter catadon), and every six minutes for 

 Tur slops truncatus. This puts very stringent requirements on the 

 relationship of the whales to other events within the sea. Each 

 whale must know where the surface of the sea is at each instant 

 and compute his future actions so that when he does run out of 

 air he is near the surface. He is essentially a surface-to-depth and 

 depth-to-surface oriented animal. He must travel at high speed 

 at times in order to recapture enough air to continue whatever 

 he is doing under the surface. This means that he must calcu- 

 late his chances of obtaining a good breath of air during rain 

 storms and similar situations. He can be violently thrown 

 around at the surface unless he comes up in the trough rather 

 than at the crest of the wave. Such calculations probably require 

 an exercise of something more than just "instinct." 



Water-breathing animals, on the other hand, have no need for 

 such calculations. If the surface gets rough, they move down- 

 ward and stay there. The required maneuvers are very much 

 simpler and the amount of computation is very much less. 



This requirement for die whales implies that the information 

 coming from every one of the senses, not just the skin, needs to 

 be correlated very rapidly and in complex patterning to allow 

 the animals to predict their future course safely and accurately. 

 It also requires the use of large amounts of information from 

 memory. 



The predators of the sea, other than the whales themselves, 

 make life in the sea rather a complex business for mammals. The 

 very large sharks can and do attack whales, dolphins, and por- 

 poises. At times such attacks are by overwhelming numbers of 

 sharks on a relatively small number of dolphins. All of the older 

 animals in our experience have at least one shark bite on them — 

 the younger animals are protected by the older ones and most of 

 them are not so dramatically scarred. 



The whales, in turn, must track their own prey in order to 

 obtain food. With the single known exception of Orca, none of 



38 



