The biparental care system of the California mouse, Peromyscus californicus

Most knowledge of parent-offspring relations in mammals is derived from studies of mother-infant interactions. Male parental care has been less well studied. We explored maternal and paternal behavior of the California mouse, Peromyscus californicus. Six pairs of parents and their young were videotaped continuously for 12 hours/day, on alternate days from Days 1 to 31 postpartum. Males exhibit all parental activities and to the same extent as displayed by mothers, except lactation. Male parental behavior begins on the day of birth. Mothers and fathers spend substantial and equivalent amounts of time in the nest and in physical contact with pups throughout lactation. Males devote more time than females to licking pups, although females engage in more pup anogenital licking. Mothers nurse for at least 4 weeks, and fathers and mothers both build nests and carry young. The biparental care system of Peromyscus californicus affords an opportunity to develop a broader, more complete view of parent-offspring relations. Most of our knowledge of parent-young relations in mam-mals is based upon studies of mother-infant interactions. It is possible that emphasis on maternal-filial interactions has given us a limited view of parent-offspring relations. The allocation of parental care in mammals is not restricted to the mother (Hrdy, 1976; Spencer-Booth, 1970; Wilson, 1975). There is a new awareness of the mammalian father as an important participant and contributor to the care and devel-opment of the young (Kleiman & Malcolm, 1981; Lamb, 1981;Wuensch, 1985). Male parental care is relatively uncommon in mammals and is found predominantly among rodents, carnivores, an