in THE STRUGGLE OF LIFE 39 



for instance, lives in an almost impregnable citadel. 

 Birds soar above pursuit, and mammals are swift and 

 strong, but among the latter the armadillos have bony 

 shields of marvellous strength, and hedgehog and porcu- 

 pine have their hair hardened into spines and quills. 

 Now do we not say that all these structures were from 

 the first of the nature of armour, indeed they admit of 

 other explanations, but that they serve as armour now 

 there can be no doubt. And just as we conclude that a 

 man would not wear a chain shirt without due reason, 

 so we argue from the prevalence of animal armour to 

 the reality of struggle. But again the struggle for 

 existence in the technical sense does not seem to us to 

 be illustrated by the use of an equipment which has been 

 long established and is shared by all the members of the 

 species equally. The struggle is seen when some mem- 

 bers use their armour in some novel and effective way. 



3. Different Forms of Struggle. We have said that 

 it is of the very nature of living creatures to be self- 

 preservative, expansive, insurgent to react against 

 difficulties and limitations. Hence struggle whether 

 for food or mates, whether for self or for others. Hunger 

 and love solve the world's problems. Mouths have to 

 be filled, but population tends locally and temporarily 

 to outrun the means of subsistence, and the question 

 ' which mouths ? ' has to be decided sometimes by 

 peaceful endeavour, as in migration, sometimes with 

 teeth clenched or ravenous. Many animals are carniv- 

 orous, and must prey upon weaker forms, which do 

 their best to resist. Mates also have to be won, and 

 lover may fight with lover till death is stronger than 

 both ; two fighting stags, for instance, sometimes inter- 

 locking their antlers fatally. But these struggles for 

 food and for mates are often strivings rather than strife, 

 nor is a recognition of the frequent keenness and fierce- 

 ness of the competition inconsistent with the recognition 

 that another mode of the struggle for existence in the 

 technical sense is some experiment in mutual aid, soci- 

 ability, and parental care. There is a third form of the 

 struggle, that between an animal and its changeful 



