MAMMALIA 



THE animals which have been dealt with in this 

 series are Mammals. They belong to the great 

 class known as Mammalia. 



A Mammal is commonly known as a warm- 

 blooded animal, that is, an animal which has a 

 fixed bodily temperature which is not affected by 

 external conditions. On the contrary, the bodily 

 temperature of a reptile fluctuates according to the 

 degree of warmth of the air or water in which it 

 happens to be living. 



Mammals all possess backbones ; they are, as a 

 general rule, covered more or less with hair, and 

 they suckle their young. 



With the exception of those remarkable Australian 

 Monotreme animals which lay eggs, all mammals 

 give birth to living young, which are reared on milk 

 secreted by the mammary glands of the mother. 

 In fact, the word Mammal means " an animal with 

 teats." The Mammals as a class are the highest 

 in intelligence of all orders of living creatures. 

 This is due to the superior development of 

 brain. Mammals, of course, vary considerably in 

 intelligence. Those possessing the most complex 

 brain, rank the highest in this respect. Man is 

 at the head of the Mammal class, and the Anthro- 



248 



