The ontogeny of a natural food aversion in domestic rats (Rattus norvegicus) and house mice (Mus musculus)

During a 1-hr feeding test, hungry domestic rats (Rattus norvegicus) that had been reared individually from weaning with a domestic house mouse (Mus musculus) were less likely (p less than .05) to feed on the intact carcass of a freshly sacrificed mouse than were rats that had been reared individually with another rat. Likewise, hungry mice that had been reared individually with a rat were less likely (p less than .01) to feed on a dead rat than were mice that had been reared individually with another mouse. Regardless of the social conditions during rearing, hungry mice were more likely to feed on a dead mouse than were hungry rats to feed on a dead rat. Taken together, the present and other findings suggest that the tendency by rats to reject conspecific flesh stems, at least in part, from prior experience with conspecifics and with their own bodies. The experiential factors mediating the tendency by mice to reject conspecific flesh remain unclear.