Gerbils reared by rats: Effects on adult open-field and ventral marking activity

Abstract

At 72 hr after birth gerbil litters were divided and half the pups fostered to lactating mother rats whose own pups were removed. Remaining pups were returned to their natural mothers. Rat-reared gerbils weighed more at weaning than control gerbils but there was no weight difference at 100 days. When tested in the open-field as adults, rat-reared gerbils were found to locomote and to rear less than controls. The fostering treatment had no clear-cut effects on frequency of ventral marking, although there was a large sex difference for this measure. No sex differences in open-field activity were found.