Maternal behavior in the rat: Survival of newborn fostered young after hormonal treatment of the foster mother


  • Aided in part by a grant from the Purdue Research Foundation and by grants GM-06263 and HD-02068 from the national Institutes of Health.


The 10-day old natural young of lactating rat mothers were removed, and the mother was given newborn foster young together with hormone treatment. A single injection of prolactin or progesterone was sufficient to increase the survival perentage and body weight of the fostered rats. An hypothesis is presented to explain the action of the hormones and the possible relationship to placental eating which is noted in many mammals at the time of parturition.