SREL Reprint #0047




An Investigation of Competition in Natural Populations of Mice


Larry D. Caldwell



Three approaches were used to study interactions between Petomyscus polionutus and Mus musculus:  (1) a 15-month study of natural populations in six 3.5-acre grids located in a large abandoned field on the AEC Savannah River Plant Reservation which is located on the Upper Coastal Plain of South Carolina, (2) a comparison of behavior and food requirements of the mice in the laboratory, (3) a 7-month study of the 2 species confined to a one acre enclosure located in the field.

No evidence of aggressive competition (fighting, etc.) was obtained by Mus was definitely at a disadvantage in competition for food when population density was high or when the 2 species were confined in the enclosure.  It is postulated that the migratory behavior of Mus is a mechanism which reduces competition between it and the more sedentary Peromyscus enabling both species to coexist in the same habitat even when Mus appears to be less well adapted to the Upper Coastal Plain environment.  



SREL Reprint #0047



Caldwell, L.D. 1964. An investigation of competition in natural populations of mice. Journal of Mammalogy 45:12-30.




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