PREGNANCY AND COPULATORY-BEHAVIOR IN RANDOM-BRED HOUSE MICE MATED IN POSTPARTUM ESTRUS

Sixteen male-female pairs of random-bred house mice were studied in a total of 61 matings in postpartum estrus. An array of behavioral measures and measures related to resulting pregnancies were determined. Measures of copulatory behavior were comparable to those in hormone-induced estrus. There was no evidence that the number of preejaculatory intromissions, the total number of intravaginal thrusts, or any other behavioral measure was related to any aspect of pregnancy measured. Thus, the paradox of a considerable amount of male copulatory behavior coupled with a low stimulus requirement for pregnancy in female house mice reported in earlier studies appears unattributable to effects of domestication, mode of estrus, or failure to permit females to carry litters to term. © 1979, The Psychonomic Society, Inc.. All rights reserved.