Reproduction 



A LL THOSE INTERESTED in whaling are quite naturally concerned 

 /_\ to know how many whales can be caught annually without causing 

 / A serious depopulation. In the next chapter we shall see that it will 

 probably take many years before there is complete certainty on this 

 subject. One thing, however, is clear: any further knowledge must be 

 based on the study of Cetacean reproduction, and on the rate at which 

 these animals multiply. Hence it is not surprising that when applied 

 biologists turned their attention to Cetaceans at the beginning of the 

 twentieth century, reproduction took pride of place in their investigations. 

 Since 1925-30, when Risting, Mackintosh and Wheeler laid the founda- 

 tions of this branch of zoology, a spate of publications has constantly 

 added to our knowledge of it. 



Despite all the work that has been done on the subject, a considerable 

 area remains shrouded in mystery. This is only to be expected in view of 

 the difficulties encountered in studying the reproductive processes of 

 terrestrial mammals, which, in contrast to whales, generally display much 

 more than just a part of their head or back to the observer, and which do 

 not migrate from the poles to the equator, while hiding the secrets of their 

 intimate life under a screen of sea. In the case of whales, therefore, 

 biologists are largely restricted to gathering what information they can 

 from whale carcasses. 



Even on superficial examination, we are struck by the fact that the 

 testes, i.e. the male sex glands, are not found in an external pouch, as 

 they are in most mammals. In fact, they cannot be seen from the outside 

 at all, and only when the abdominal cavity has been opened and the 

 intestines removed or pushed aside, do we find them behind, and lateral 

 to, the kidneys, in the form of two fairly elongated cylindrical organs with 

 a white, smooth and shiny surface (Fig. 192). But even when we have 

 found them, the testes at least of the big whales are difficult to handle 

 for closer examination, since in Blue Whales they may be more than two 



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