actions by males, especially among nonhuman animals, that are directed toward care of their young. Direct paternal behavior consists of such actions as feeding, carrying, or otherwise nurturing the offspring; it is thought to be rare, given that many males lack certainty of paternity. Indirect paternal behavior consists of acquiring resources or defending the group from harm, which indirectly leads to increased survival of the young. Males of species with biparental care undergo some hormonal changes similar to those in females: increased secretion of prolactin and estrogen. Early experience with young offspring is important for competent paternal behavior in many species. See also maternal behavior; parental behavior.