Parental Behavior and Hormones in Non-Mammalian Vertebrates

Abstract

Parental care has evolved multiple, independent times in non-mammals, resulting in a great diversity of parental care systems and behaviors. As in mammals, it is likely that hormones regulate many aspects of parental care, yet such regulation has been greatly understudied, especially in amphibians and reptiles. Nonetheless, hormones such as vasotocin appear to have a role in parental care in some frogs and snakes. In fishes, male care is most prominent, and the hormonal mechanisms which promote nest site defense often promote paternal care. In addition, prolactin, isotocin, and glucocorticoids regulate parental behaviors in both sexes. In birds, sex steroids and prolactin are important for incubation initiation and maintenance. Prolactin, glucocorticoids and other hormones appear to be involved in almost all aspects of post-hatch parental care. Across non-mammalian vertebrates, additional experiments that manipulate hormones are needed to determine if correlations between hormones and parental behavior reflect causal relationships.