1. The Social Use of Space 75 



Such psychological dominance also develops among members of a single 

 species, at least at the higher levels of the interspecific hierarchy. We have 

 already presented the data and logic which gave rise to the concept of 

 constellation formation. On the average, each constellation has one central 

 alpha member with a very large home range, six beta members with home 

 ranges slightly smaller than for alpha individuals, and five gamma members 

 with markedly restricted home ranges. Such intraspecific differences in 

 home range size suggests that, among alpha (C or D types in above dis- 

 cussion) species at least, developmental alterations in vocalization arise. 

 Gamma members of alpha species exhibit a minimum complexity of 

 vocalization. Successively beta and alpha members increase the complexity 

 of their vocalizations. All members of the species presumably have the 

 same level of filter development. Even so, the differences in complexity of 

 vocalization should result in alpha members mainly ignoring vocalizations 

 of beta and gamma individuals insofar as these signals have a negative 

 valance. Beta members respond not only to other beta individuals but to 

 their alpha associates. Gamma members not only treat the vocalizations 

 of other gamma members as inhibitory stimuli, but are likewise similarly 

 influenced by those from their beta and alpha associates. 



It must be borne in mind that this whole discussion of vocalizations and 

 filters in the context of the small mammal community is strictly theoretical. 

 However, it not only provides a conceptual framework offering one inter- 

 pretation of empirical data, but also enables formulations capable of ex- 

 perimental analysis. 



A study of the complexity and intensity of vocalizations is suggested as 

 having priority in testing the theory. Sorex, Blarina, Peromijscus, and 

 Clethrionomys, respectively representing theoretical types A, B, C, and D 

 discussed above, should serve as particularly useful subjects, especially 

 since they all may occur in the same small-mammal community. The vocali- 

 zation of each higher member of the series should include the basic char- 

 acteristics of all lower ones and in addition possess characteristics not held 

 by lower members in the series. Furthermore, if each of these species is 

 experimentally exposed to a conditioned avoidance situation where vocali- 

 zations of their own species serve as a conditioned stimulus, one may 

 anticipate that vocalizations of the other members of the series will equally 

 well induce avoidance upon their replacement of the intraspecific stimulus 

 only if the vocalization represents a higher member of the series. Unfortu- 

 nately, the extreme paucity of om* knowledge of vocalizations of small 

 mammals necessitates these suggestions in lieu of any firm experimental 

 evidence. 



Development of cryptic behavior forms an ancillary aspect of this con- 

 cept. The lower-ranked shrews typically spend much of their time in under- 



