Why do baby sharks, hyenas, and pelicans kill their siblings? Why do beetles and mice commit infanticide? Why are twins and birth defects more common in older human mothers? A Natural History of Families concisely examines what behavioral ecologists have discovered about family dynamics and what these insights might tell us about human biology and behavior. Scott Forbes's engaging account describes an uneasy union among family members in which rivalry for resources often has dramatic and even fatal consequences. In nature, parents invest resources and control the allocation of resources among.