This book presents a comprehensive review of various biological and ecological studies in animal science, including their embryology, evolution, classification, habitats and distribution. Topics discussed herein include the prophenoloxidase system in insects; cloacae, cloacal glands and female sperm storage in giant salamanders; anxiety, aggression and social behavior in zebrafish; the shifting and transition mode of verterbrate genome evolution; fish lectins; nutritional consequences of extreme sexual size dimorphism; feeding behavior of herbivores in rocky outcrops of northwestern Patagonia; the morpho-physiology of the brown dog tick; vertebrate biodiversity and its relationship to peptide hormone evolution; classification of dinosaurs from the anatomical viewpoint; allergen exposure and the development of insect bite hypersensitivity in horses.