Cooperative System Amongst Lower Animals 760 -. 



'. ."' ■ 

 (^25: 9) says: "Not only do they outnumber in individuals . 

 all other terrestrial animals, but their colonies even in very 

 circumscribed localities often defy enumeration. Their col-' 

 onies are, moreover, remarkably stable, sometimes outlasting 

 a generation of men." * 



Now, as the above author elsewhere points out, the total 

 number of ant species is relatively small, their dominance 

 nevertheless is preeminent. And the result has been secured, 

 not by predatory and competitive methods between them- 

 selves, or even against other animals to any great degree, 

 seeing that ants are largely vegetarian. It is due to combined 

 social habits and excellent kinds of defense, alike on the part 

 of the individual and the community. Their systems of de- 

 fense have made them respected by other animals, and so 

 Wheeler says (225: 4): "The dominance of ants is clearly 

 indicated by the small number of their enemies. They are 

 preyed upon by comparatively few mammals, birds, reptiles, 

 parasitic insects, and other ants." 



So the "successful" species of animal are not part of the 

 most numerous species of a class, but rather restricted species 

 that have developed an advancing nervous and social organi- 

 zation, alongside, it may be, many related genera or species 

 that do not so develop. 



We may now pass in review some of the evidence yielded 

 from higher invertebrates up to man. 



Although of a simple and elementary nature, the social 

 relation of young spiders to their mother, in such genera as 

 Pardosa, where the former may be carried about for several 

 days on the backs of the latter, or the social life of the young 

 for ten to fourteen days in the web-spinning Epeira (179: 340) 

 represent commencing social organization, even though later 

 these individually become ferocious carnivores. Again the 

 genus Uloborus includes several species with marked social 

 habits. But the nervous complexity of none of these has as 

 yet been compared with that of other spiders of non-social habit. 



But amongst invertebrates it is in some groups of insects 

 that the most elaborate social and cooperative organization 



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