Have you ever wondered why some animal parents care for their young while others don't?"" Hartman never does answer that opening question directly; toward the end she notes merely that ""each system has evolved for a particular species of animal and appears best suited for the group that uses it."" Nor do her examples of how different animals care for their young bring out their evolutionary logic as do Dorothy Hinshaw Patent's nature books. Hartman's readers will learn about different mechanisms whereby parents and offspring recognize each other for feeding purposes, about the roles of fathers and parental helpers in different species, about the need for animal parents to break the ties with grown offspring, and about the peculiarities of maternal behavior in different species, such as koala bears and fungus-growing ants. Reasonably informative in the particular, but without much intellectual starch.