20 THE INFANCY OF ANIMALS 



more lowly relations, are unable to hold on of themselves, 

 but must be carried in the arms of one or other of the 

 parents, or in a sling of some kind. Among the apes and 

 monkeys they are carried by the mother either at her 

 breast or on her back, the young one gripping her fur 

 with hands and feet. Some of the lemurs have adopted 

 a plan of their own ; the young one attaching itself 

 transversely across its mother's abdomen, its head 

 resting against one flank, its hind-quarters against the 

 other, holding on by gripping her fur with hands and 

 feet, and, as an additional anchor, curling its long tail 

 round her loins. Others adopt the more normal plan as 

 shown in our illustration. 



In the matter of the number of young produced at a 

 birth we are confronted with some puzzling facts. It is 

 generally held that this number is regulated, or determined, 

 by the incidence of the mortality due to the ravages of 

 predatory animals, disease, or accident, so that species 

 in which the average duration of life is short must produce 

 a large number of young and at a rapid rate. 



The Rodents, as a group, are exceedingly prolific. Young 

 mice may themselves become parents within six weeks 

 of their birth ; and by the end of the year may contem- 

 plate their descendants to the sixth or seventh generation 

 — a formidable host when we remember that ten may 

 be produced at a birth. And mice, it is to be remembered, 

 form no inconsiderable portion of the diet of hosts of 

 carnivorous birds and beasts. 



On the other hand, the antelopes, for example, produce 

 but one young at a birth, annually ; and in spite of the 

 fact that they are constantly harassed by large carnivora 

 like lions and hunting-dogs, and have to contend with 

 prolonged periods of drought. Certain species, like the 



