Parental Behavior

Chapter 2 describes the types of parental behavior that can occur in vertebrates: maternal, paternal, and alloparental behavior. The dominant form of parental behavior in mammals is a uniparental maternal care system, where the mother raises her offspring by herself. A mother can form either a nonselective or selective bond with her infants, depending on the maturity of her infants at birth. A biparental care system, in which both maternal and paternal behavior occur, is present in about 5% of mammalian species. Approximately 3% of mammalian species exhibit a cooperative breeding system, where some offspring remain in their social group and help their parents raise subsequent offspring. The parental behavior of these helpers is referred to as alloparental behavior. The occurrence of paternal and alloparental behavior shows that alternative mechanisms, not requiring pregnancy and parturition, can evolve which allow for these forms of parental behavior.