THE IMPORTANCE OF SOCIAL LIFE 77 



mals gain companionship by even the most loosely arranged 

 collections, and there has yet to be found a completely 

 solitary organism. Peace and security is the reward offered 

 the social ant which gives itself utterly to the community. 

 Birds and mammals add the enjoyment of play and learning 

 association to other benefits; and man gains still more 

 through the continuity of tradition and understanding. 



Even the size of a group has a bearing on success or fail- 

 ure. African observers say that about 30 individuals in a herd 

 of elephants are necessary if the group is to survive. Birds usu- 

 ally do much better in large aggregations. Some gulls do 

 not lay eggs if the group is too small, and it is generally 

 agreed that the presence of many birds is necessary as a 

 stimulus to reproductive activity. Many kinds of animals eat 

 more in the presence of others, and this includes monkeys 

 and men. J. C. Welty put goldfishes in groups of four in 

 aquaria and found that they ate more of a measured food 

 supply and at a faster rate than if isolated. Other fishes show 

 similar results even though the kinds chosen did not run in 

 schools. Although there are exceptions, the general rule is 

 that children learn better and faster in classes (if not too 

 large) than by themselves under private tutors. 



As soon as the organization of a group evolves above the 

 level of loose aggregations and becomes stratified, with divi- 

 sion of labor, the benefits become very obvious. The co- 

 operation becomes orderly and efficient. There are varying 

 degrees of real organization, with the ants and other social 

 insects at the top of the list. Birds and mammals in many 

 cases show strong instincts toward an efficient spacing of 

 their populations and, by control through territorial rights, 

 eliminate much, if not nearly all, of the intraspecies com- 

 petition that would otherwise make the economy of the 

 species difficult. At mating-time this territorial instinct en- 

 courages monogamy and often involves care and teaching 

 of the young by the males, a form of family life that is cer- 

 tainly an advance in social relations. Disease and the ravages 



