Ocean Life 165 
Model of sperm whale. 
Whales are the biggest animals that exist on earth today. 
Although they live in the sea, they are not regarded as fishes 
inasmuch as they are warm-blooded, give birth to live off- 
spring, and must breathe air. Even though they can reach 
great depths they must come to the surface in order to get a 
fresh supply of life- sustaining oxygen. When they expel the 
Model of humpbacked whale. 
