u6 PROBLEMS OF EVOLUTION 



of tithe commutation, was often " the parson's pig." But these 

 are trifling details that must not prevent us from seeing the main 

 fact, that the day of the serious working of Natural Selection is 

 put off. Among birds even the praecoces, which emerge from 

 the shell able to walk, are shielded by their mothers from the 

 cold, have food found for them, are taught what is good to eat 

 and what is not, and are protected from enemies. Only the 

 Megapodes, when the sun has hatched their young for them, 

 take upon them no paternal duties, but leave their offspring to 

 do the best they can for themselves. 1 Among mammals the 

 better system is in full swing, and, difficult as it is to define our 

 meaning when we speak of an animal as high or low in the scale, 

 we may say, at any rate, that the nursing of the young its com- 

 parative completeness and its duration is a criterion that must 

 not be left out of sight. Looking at it as evolutionists, we see 

 in it a means of preventing indiscriminate elimination. The 

 parents use the surplus energy and means of subsistence that are 

 theirs during the pauses of the struggle for existence to save 

 their young from storm and stress. Or we may put it in this 

 way : the bringing up of their offspring is itself one of the crises 

 which the adult members of the species must be able to meet, or 

 else the species must be exterminated. When once the parents 

 discontinue their fostering care, then begins for the young the 

 unmitigated incidence of Natural Selection. But, by now, small 

 congenital differences, so small that the young nestlings or baby 

 mammals were perhaps indistinguishable, have had time to make 

 themselves appreciable. In the young family some are strong 

 and some are weak, some have one characteristic in a marked 

 degree and some another. One young crow is more cunning, 

 another from the same nest is stronger on the wing. Hence 

 when elimination takes place, it is less indiscriminate than it is 

 among the eggs of the cod or among the infant codlings. 



We must not forget that the clever and brave among birds 

 and mammals will succeed in protecting their young far better 

 than the stupid and cowardly. Hence there will be an increase 



1 See Dr F. H. Guillemard's Cruise of the Marchesa for an account of the habits 

 of the Maleo. 



