Nipple attachment in rats during the first 24 hours of life.

Abstract

Nipple attachment in laboratory rat pups during the 1st 24 h of life was investigated, and determinants that influence its expression were identified. Nipple attachment was age dependent: 1 h old pups exhibited a low percentage of attachment, and 12 and 24 h old pups exhibited high percentages when tested against an anesthetized lactator. Several factors that might influence the nipple-attachment time course were investigated. The time course was age related. The behavioral mechanism responsible for the increase in attachment from h 1 to h 12 was explored. Nipple experience, independent of milk acquisition, was the factor responsible for the increase. Learning may be employed as a behavioral strategy by the newborn, and the value of using species-relevant measures in the assessment of behavioral development is re-emphasized.