Use of a Resident-Intruder Paradigm to Measure the Influence of Environmental Adaptation on Mounting Behavior

Abstract

The course of adaptation to familiar environments was measured with a resident-intruder paradigm in which length of prior adaptation was varied and the outcome of male albino rats’ competitive, homosexual mounting encounters was observed. The percentage of total mounts in which the resident was the mounter varied directly with the duration of the resident’s prior adaptation, reaching 90% after 3 min. Longer adaptation periods did not increase this percentage significantly. Removal from an environment for up to 3 min. did not reduce the resident’s mounting dominance in that environment nor did the presence of another animal alter the course of adaptation. Odor associated with straw bedding was the primary sensory cue used by rats to distinguish different environments. The generality of the resident-intruder method was discussed.