Paternal care

In biology, paternal care is parental investment provided by a male to his own offspring. It is a complex social behaviour in vertebrates associated with animal mating systems, life history traits, and ecology. Paternal care may provided in concert with the mother (biparental care) or, more rarely, by the male alone (so called exclusive paternal care). In biology, paternal care is parental investment provided by a male to his own offspring. It is a complex social behaviour in vertebrates associated with animal mating systems, life history traits, and ecology. Paternal care may provided in concert with the mother (biparental care) or, more rarely, by the male alone (so called exclusive paternal care). The provision of care, by either males or females, is presumed to increase growth rates, quality, and/or survival of young, and hence ultimately increase the inclusive fitness of parents. In a variety of vertebrate species (e.g., about 80% of birds and about 6% of mammals), both males and females invest heavily in their offspring. Many of these biparental species are socially monogamous, so individuals remain with their mate for at least one breeding season. Exclusive paternal care has evolved multiple times in a variety of organisms, including invertebrates, fishes, and amphibians. Male mammals may invest heavily in reproduction through efforts to enhance reproductive success (e.g., courtship displays, intrasexual combat) or to provide paternal care. However, the costs of paternal care have rarely been studied in mammals, in large part because only 5-10% of mammals exhibit such care. Nonetheless, in those species in which males do provide extensive care for their offspring (i.e., biparental species, including humans), indirect evidence suggests that its costs can be substantial. For example, mammalian fathers that care for their young may undergo systematic changes in body mass and in circulating or excreted concentrations of a number of hormones (e.g., androgens, glucocorticoids, leptin) as a function of reproductive status, and several of these hormones have important effects on body composition, metabolism, and organismal performance. Nonetheless, the energetic and performance consequences of male parental investment have rarely been investigated directly in mammals. In mammals, paternal care is found most commonly in primates, rodents and canids. Human cultures and societies vary widely in the expression of paternal care. Some cultures recognize paternal care via celebration of Father's Day. According to CARTA , human paternal care is a derived characteristic (evolved in humans or our recent ancestors) and one of the defining characteristics of Homo sapiens. Different aspects of human paternal care (direct, indirect, fostering social or moral development) may have evolved at different points in our history, and together they form a unique suite of behaviors as compared with the great apes.One study of humans has found evidence suggesting a possible evolutionary trade-off between mating success and parenting involvement; specifically, fathers with smaller testes tend to be more involved in care of their children. Research on the effects of paternal care on human happiness have yielded conflicting results. However, one recent study concluded that fathers generally report higher levels of happiness, positive emotion, and meaning in life as compared with non-fathers. According to the United States Census Bureau, approximately one third of children in the U.S. grow up without their biological father in their home. Numerous studies have documented negative consequences of being raised in a home that lacks a father, including increased likelihood of living in poverty, having behavioral problems, committing crimes, spending time in prison, abusing drugs or alcohol, becoming obese, and dropping out of school. In non-human primates, paternal investment is often dependent on the type of mating system exhibited by each species. Mating systems influence paternity certainty and the likelihood that a male is providing care towards his own biological offspring. Paternal certainty is high in monogamous pair-bonded species and males are less likely to be at risk for caring for unrelated offspring and not contributing to their own fitness. In contrast, polygamous primate societies create paternity uncertainty and males are more at risk of providing care for unrelated offspring and compromising their own fitness. Paternal care by male non-human primates motivated by biological paternity utilize past mating history and phenotypic matching in order to recognize their own offspring. Comparing male care efforts exhibited by the same species can provide insight on the significant relationship between paternity certainty and the amount of paternal care exhibited by a male. For example, Siamangs (Symphalangus syndactylus) utilize both polyandrous and monogamous mating systems but, it was found that monogamous males are more likely to carry infants and contribute to parental duties compared to those in promiscuous mating systems. Studies in Primatology have used primate mating systems and social organization to help theorize the evolutionary significance of paternal care in Primates.