Animal Locomotion, Flying and gliding animals, Types of aerial locomotion, Ecology of aerial locomotion, Biomechanics of aerial , Invertebrate, Arthropod, Mollusca, Vertebrate, Fish, Amphibian, Reptile, Bird, Mammal, Origin of avian flight, Flight Characteristics, Theories, Terrestrial locomotion, Legged locomotion, Stance, Number of legs, Animal locomotion on the surface layer of water, Meniscus climbing, Bioenergetics, Feather, Structure and characteristics, Evolution