^■"- ^507 RODENT ETHOLOGY — EISENBERG 3 



The study of social organizations ultimately led to an extension of 

 the comparative method. A given type of social organization has a 

 characteristic structure. The structure is the summation of the form 

 and frec^uency of each type of interaction within an mteracting group. 

 Thus, the social structure reflects the mechanisms of interaction and 

 the adaptive role of the interaction patterns determines the selective 

 advantage of the S3'stem at the level of the individual member. On 

 the other hand, a set of complementary emergent properties results 

 when one considers that the social structure itself reflects an adapta- 

 tion to a given set of en-sironmental relationships that are reflected in 

 the physiology or metabolism of the social group taken as a whole. 



Future research on the adaptive nature of whole societies will 

 necessarily have to concern itself with biologically \dable societies, 

 i.e., a social unit or series of social units that are maintaining their 

 numbers over long periods of time. In essence, then, conclusions 

 concerning the adaptive nature of groups must be based on groups 

 exhibitmg a prevailing reproductive success. 



The interrelationships of the various measurable phenomena 

 exhibited at the level of the individual and the group are presented in 

 figure 1. 



Adaptive 

 Nature of the Q= 



Social Structure 



Mechanisms 

 of Interaction 



Metabolism of the 

 Social Structure 



^Adaptive R6le 

 of Interaction 



Figure 1.^ — Diagram indicating two possible levels of analysis commonly applied to social 



structures. 



The present report thus demonstrates a method for the analysis of 

 mammalian social structure, the application of the methods to several 

 famOies showing varying degrees of convergence or parallelism, the 

 reformulation of the term "species-specific behavior," and a dis- 

 cussion of social evolution within the Rodentia. 



