EVIDENCE THAT MATERNAL VENTRAL SKIN SUBSTANCES PROMOTE SUCKLING IN INFANT RATS

Washing a lactating rat''s ventral skin with acetone, alcohol and water markedly reduces the effectiveness with which her 2-wk-old infants can initiate suckling on the anesthetized mother. Control experiments with detailed thermal and behavioral measures give evidence tending to rule out lowered skin temperature, altered thermal gradients, changed tactile characteristics of abdominal fur or nipples and aversion to remaining traces of the organic solvents as responsible for the infants'' failure to find and attach to nipples. The data suggest that some substance(s) on the skin of the mother''s ventrum act as olfactory and/or gustatory cues for the infants'' orientation and attachment to nipples.