Foetuses are less effective than pups in eliciting murine parental behaviour

Abstract
Forty‐four virgin female albino mice were presented individually on one occasion only, with either a three‐day‐old pup or a foetus removed on the eighteenth day of pregnancy. The stimulus‐objects in question had all been frozen, defrosted and washed, in order to minimize differences between them. The foetuses did have some capacity to elicit parental behaviour but pups were more effective in this respect. Although for the present any interpretation in terms of infantile signals is difficult, these results indicate that adults, even when presented with dead animals, are adapted to respond to a pup more than to a foetus.