ASSOCIATION 105 



Association immediately affects selection and survival. 

 Life in groups affords protection from extremes of cli- 

 mate and from ferocious animal enemies. In the snow 

 storm, sheep press together and keep warm. Certain 

 animals move in herds and flocks, so that in case of 

 danger they are able to stand off the enemy. The iso- 

 lated animal unable to sustain bodily warmth in the face 

 of the blizzard, succumbs. A fierce enemy is more sure 

 to exterminate the single individual. In this way it 

 happens that sociability has a definite survival value, for 

 the individual accustomed to group life is selected to 

 survive, while the individual living an isolated existence 

 lacks the advantage of cooperation and is more often 

 destroyed. 



Life in societies insures a larger and a more certain 

 food supply. Social animals hunt in packs, when their 

 combined strength is often able to vanquish prey that 

 one of them could not overcome singlehanded. More- 

 over, food secured by one of the pack is often shared with 

 the other members, while an unsocial animal would be 

 driven from the feast. 



But the great effect of association and group life upon 

 selection is found in the fact that through the advantages 

 of protection and food supply gained by cooperation and 

 mutual aid, the average social animal has a better chance 

 to reach maturity and have offspring. Under the safer 

 conditions of group life, more progeny can reach ma- 

 turity than is possible in the uncertain state of isolated 

 families. In a previous chapter we saw that survival 

 meant more than continuance of mere individual life : it 

 meant the perpetuation of the race by the rearing of 

 progeny. Survival in this sense means that certain ad- 

 vantageous characteristics possessed by the parents, will 



