Measuring of the postcopulatory departure in male rats.

Spontaneous departure from the female was observed in male rats during testing of instrumental sexual responses. Male rats were tested in an apparatus consisting of two compartments connected by a runway composed of four parallel corridors. The final corridor of the runway and the goal compartment as well as the goal compartment and the start compartment were connected by one-way doors enabling the male to run only in one direction. An incentive female was tethered in the goal compartment. After contact with the female, lasting up to the end of a mount bout, or after exploration of the goal compartment, if the copulatory behaviour was not displayed, the male spontaneously passed to the start compartment and a new run started thereafter. The male thus performed the runs through the apparatus without any intervention from the experimenter.