Olfaction and Maternal Behaviors in Rats

Abstract

The research on maternal behaviors and maternal responsiveness is extensive. Maternal responsiveness in rats consists of retrieval ofpups to the nest, grouping pups, building the nest, and licking and nursing of the pups. There are studies suggesting that audition, vision, olfaction, and vomeronasal (VNO) function play a role in the task of maternal responsiveness. Some research demonstrates that odors play no role in responsiveness while other research suggests odors are required (Alberts & Farrell 2002 b). The ability to recognize offspring has been credited to the olfactory epithelium as well as the VNO. The current research analyzed the role of the olfactory epithelium in offspring recognition and retrieval in female rats. Pups were placed in two treatment groups; one group was painted with citrus scented oil (containing volatile chemical odorants) on days two through six postpartum, the second group was painted with citrus oil on days seven through eleven postpartum. Pups were removed from the nest and dispersed throughout the home cage. The time it took mothers to retrieve dispersed pups back to the nest was measured. The treatment used contained volatile chemical odorants detected by the olfactory epithelium, which had no significant effect on maternal responsiveness and pup retrieval. From this research no evidence was found to support the hypothesis that the nasal epithelium plays a role in retrieval and recognition. Because the olfactory epithelium was found not to function in maternal responsiveness the findings support previous research suggesting the VNO as the main player in maternal responsiveness in rats.