The four-volume Encyclopedia of the Animal World set offers young readers an appealing introduction to major animal groups and species alive today. Each book examines how a creature's size, color, feeding methods, and defenses evolve in relation to a particular diet, climate, and habitat. Also explored are the human activities that often disrupt natural ecosystems and threaten the survival of many species. Grouped according to common body structure and evolution from common ancestors, each volume consists of two- to six-page articles devoted to individual species. Each article includes a fact panel that provides information at a glance on the world distribution, habitat, group size, diet, lifespan, scientific name, and conservation status of every species.