WHALES 



THE shape which Nature has given the Whale is 

 perfectly adapted for navigating the vast oceans. 

 To render the body as inconspicuous as possible 

 to enemies, the Whale's back is dark, and the lower 

 parts are usually white. It has one drawback, 

 however. The Whale, like all other warm-blooded 

 mammals, obtains its life-giving oxygen direct from 

 the air ; it is therefore obliged to live upon the 

 surface of the water most of its time. When it 

 dives it has to come up again to breathe. The 

 nostrils open separately, or more usually by a single 

 opening on the top of the head. When the Whale 

 comes to the surface, its first act is like that of a 

 man who comes up after a long dive. It discharges 

 the vitiated air from its lungs before filling them 

 again with fresh air. The air is driven out of the 

 Whale's lungs with such force that it ascends to a 

 considerable height. This air is saturated with 

 water at a high temperature, and on coming in 

 contact with the colder outer air, the warm vapour 

 in the expired air condenses and forms a column 

 of steaming mist which is visible at a great distance. 

 Often, however, a Whale begins to discharge the 

 air from its lungs before the nostrils are actually 

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