82 ANIMAL AGGREGATIONS 



community is to be compared, rather than to the highly integrated 

 ant or bird or man. In human society we are accustomed to the idea 

 of community integration. Thus a village is composed of a number 

 of families which are connected as a unit not only because they oc- 

 cupy a limited amount of contiguous space but also because they 

 are bound together by social organizations such as church and 

 school, by economic relationships of kinship or of marriage; all of 

 these knit the community into a working unit. The organization 

 is loose. Individuals may come and go. Whole famihes may depart 

 and others move into the village, and yet the village retains a defi- 

 nite unity, with a more or less marked individuality which may be 

 quite distinct from that of neighboring communities. 



In such a community as the village, men are associated not only 

 with each other but with other animals. There are the horses that 

 supply part of the draft power; cattle that give meat and milk; 

 dogs and cats that provide companionship and amusement to man, 

 feed on his surplus food or on other associated animals, add to the 

 dirt of his household and scatter bacteria and parasites; flies that 

 feed on the refuse of man and breed in the excreta of his commen- 

 sals; mosquitoes that breed in water reservoirs and feed on man 

 and other animals; birds attracted by the nesting sites and food to 

 be found near man; rats and mice similarly attracted, and snakes 

 attracted by the birds and rats and mice; insects that prey on gar- 

 dens and orchards, and insects that prey upon these; as well as 

 other animals with little direct relationship to the community but 

 occupying the same general space. 



If a progressive town board decides to instal a hydroelectric plant, 

 the river is dammed and a breeding place is furnished for thousands 

 of mosquitoes; if some of these are Anopheles, the malarial parasite 

 may become prevalent. The breeding range of fish and of pond in- 

 sects is extended at the same time that the human population is ad- 

 justing to the use of cheap water power ; the dam is a matter of con- 

 cern to the whole animal community. 



The consequences of an unusually mild winter ramify also through 

 the entire community. One result is that many insects live over 

 which would ordinarily be winter-killed. These attack orchard, gar- 



