BROOD-CARE AMONG MAMMALS 175 



to follow her. Young ungulates have to follow the mothers almost 

 from the first ; it is only in a few rare cases, such as the pigs, that they 

 are kept for any time in a lair. It is still rarer for them to be carried 

 by the mother ; the hippopotamus and the hyrax are very unusual 

 in this respect, and the former has habits different from those of 

 all other ungulates, whilst the latter belongs to a peculiar and isolated 

 group. Young ungulates, like all mammals, are suckled by the 

 mothers, but are not fed by her in any other way. Certainly parental 

 affection is strong, but it is the business of the young one to find, follow 

 and stick to the mother rather than for the mother, as amongst car- 

 nivores, to take the initiative. And the most important difference of 

 all is that whilst no doubt the young find the feeding-grounds by 

 following the mother, there is practically no real training of the 

 young by their parents. 



The Insectivora are the living survivors of a very ancient type of 

 mammal, certainly older than the carnivores, and perhaps repre- 

 senting their ancestors. Most of them are small and shy creatures, 

 lurking by day in holes or burrows and coming out at night in 

 search of worms and beetles. The family is generally small, four 

 or five at most, and is born in a helpless condition, frequently blind 

 and nearly naked. The female hedgehog prepares a nest of 

 moss and leaves, placed so that it is sheltered from the rain, and 

 the naked young are too helpless even to roll themselves up at 

 first. In a week or two they begin to play, the spines harden, and 

 the mother teaches them their future diet by bringing worms and 

 beetles to them. The female shrew constructs a globular nest at the 

 end of a blind burrow and lines it with soft hair and leaves. So also 

 the mole selects a spot where two of its burrows meet, and constructs 

 a globular chamber, very different from the elaborate fortress 

 which is its usual home, to serve as a nursery for the helpless young. 



The members of the huge group of rodents vary in size from the 

 South American capybara, which may reach four feet in length, to 

 the pigmy fieldmouse, the smallest of living mammals, and although 

 they are all gnawing, chiefly vegetarian creatures, differ much in 

 habits. Amongst them are the most prolific of mammals, but the 

 rapid rate of multiplication is achieved by the shortening of the 

 period of youth, and by the early age at which individuals begin to 

 breed, rather than by the size of the broods. In many cases there 

 are only two, three, or four born at a time, although there are some 

 cases where the number may reach ten or a dozen. In most rodents 

 the young are born naked, blind and helpless, and the young depend 



