120 



WHALES 



a much gentler inhalation before it closes the blowhole and dives down 

 once more. The huge back with its small dorsal fin comes up for a 

 moment (Figs. 3 and 55), the impressive flukes, gleaming white beneath 

 and black on top, wave through the air, and then the whale is gone, almost 

 straight down. The flukes tell us that we have just seen a Humpback 

 Whale, for other Rorquals rarely bring their flukes up out of the water. 



We might have gathered this from the shrill vibrato of its blow alone, 

 for other Rorquals produce a deep lowing noise, while dolphins and 

 porpoises emit 'sighs'. On a still summer evening these sighs can often be 

 heard from many North Sea piers, and holiday-makers rarely forget this 

 weird sound. But to return to our Humpback. From the fact that its flukes 

 came up, we can tell that its dive will be long and deep, and that the 

 animal will be submerged for the next 10-15 minutes. Our ship resvimes 

 its original course, and the passengers return to their interrupted pastimes, 

 unless some of them are interested enough to wonder what really happens 

 when a whale blows. Clearly, it is a form of respiration since, being 

 mammals, whales must replenish the air in their lungs above the surface. 

 This is rather unfortunate for them, for if they had gills instead of lungs 

 they would be almost safe from human pursuit. 



Though it was formerly thought that whales blew water, our own eyes 

 have shown us that this is not so. We have seen that the nostrils - the blow- 

 hole - do not open vmtil they break surface and we know that what 

 emerged from them was condensed vapour, just like our own breath on a 

 cold winter's day. Vapour appears whenever breath is cooled suddenly, 

 and hence the whale's blow is particularly distinct in polar seas, though, 

 as we have seen, it appears in the tropics also, and Layne reports that even 

 in the heat of the Upper Amazon, the Boutu's blow can be seen to a height 

 of 6 feet. 



The explanation is therefore not so much the climate, as the fact that 



Figure 70. J. SteVs drawings of two Sperm Whales seen from S.S. Breda off S. America 

 on 31st May and 2nd July, iij55. 



