Interactions of strain of male and female on the mating behavior of the rat

Copulatory behavior of male and female rats from eight genetically distinct strains was studied. The design allowed for a separation of male, female, and interactive genotypic effects. The pattern of genetic variation varied according to the particular combination of genotypes used. Large differences in body weight and genetic origins resulted in substantial interactive effects; conversely, the copulation of animals from similar backgrounds and of similar size was determined chiefly by the male genotype.