Maternal contributions to the development of masculine sexual behavior in laboratory rats.

Maternal licking was manipulated by lining the nasal passages of rat dams with polyethylene tubing to interfere with their olfactory competence. Olfactory cues from pups elicit maternal licking and handling, particularly of anogenital regions, and dams with olfactory deficits were observed to lick their pups less. Mature male and female offspring of these dams and their controls were gonadectomized, treated with testosterone propionate, and tested for masculine sexual behavior. The male offspring of dams that provided less maternal licking had longer ejaculatory latencies, longer post-ejaculatory intromission latencies, and longer inter-intromission intervals than controls. Female offspring of the intubed dams performed fewer mounts and intromissions, had longer intromission latencies, and longer inter-intromission intervals. It was concluded that stimulation from maternal licking contributes toward the development of a mechanism that underlies the timing of copulatory rate.