Transnatal olfactory continuity in the rabbit: behavioral evidence and short-term consequence of its disruption

This study investigates the role of prenatal odor learning on postnatal adaptive orientation responses in the newborn rabbit. Preference tests revealed that pups are equally attracted to the odors of placentae and colostrum (Experiments 1-4), suggesting that an odor continuity may exist between the fetal and neonatal environments. To test some predictions derived from this hypothesis, we manipulated the odor of the diet of pregnant-lactating does to control the chemical niches of their perinates. Fetuses exposed in this way to the odor of cumin (C) were selectively attracted as neonates to the odor of pure C (Experiment 6). Prenatal exposure to C also was followed, to a certain extent, by enhanced attraction to C odor in the placenta or colostrum from females which had consumed it (Experiments 5 & 7). Finally, the functional implications of perinatal odor continuity were tested by disrupting it. The odor component of the feto-neonatal transitional environment revealed indeed to affect the ability of certain pups to gain colostrum and milk at the very first sucking opportunities (Experiment 8).