Document Type


Date of Award



Agonistic behavior in animals, Rodents, Population

Degree Name

Doctor of Philosophy (PhD)


Biological Sciences

First Advisor

John J. Christian

Second Advisor

John L. Fuller

Third Advisor

Donald W. Kaufman


It is hypothesized that interspecific aggression between Peromyscus leucopus and Microtus pennsylvanicus influences levels of ACTH, and thus depresses the reproductive potential of one or both species. Exposure of maturing young to interspecific aggression might be especially critical since the most effective means of reducing reproduction within a species is by inhibition of maturation rather than by the depression of reproduction in mature mammals (Christian, 1971a; Dorfman and Shipley, 1965; Terman, 1968).

Consequently, laboratory investigations were conducted to determine the nature of behavioral interactions within and between groups of Peromyscus leucopus and Microtus pennsylvanicus. The effects that the intra- interspecific aggressive interactions might have on reproduction, movement and mortality for each species were then examined.