allonursing
n. the provision by a female of nourishment for offspring that are not her own. Although seen in rodents, ungulates, primates, and other mammalian species, allonursing remains poorly understood in light of the fact that lactation imposes substantial physiological costs on mothers and thus seemingly should not be directed toward foreign offspring. The various explanations offered for this behavior include the parenting hypothesis, stating that the individual is practicing to improve her maternal skills; the reciprocity hypothesis, stating that the individual helps one who has helped her by sharing responsibility for nourishment; the misdirected parental care hypothesis, stating that the individual is unaware the offspring is not her own; the milk evacuation hypothesis, stating that the individual nourishes others to get rid of surplus milk not consumed by her own offspring; and the kin selection hypothesis, stating that the individual obtains greater
inclusive fitness by nourishing offspring to whom she is indirectly related. Additionally, allonursing may have social benefits similar to those of allogrooming. Also called communal nursing; nonoffspring nursing.