Metamorphosis is the process of transformation that anuran amphibians undergo from hatching to adulthood. The larvae undergo major changes, both anatomical and physiological, since they will have to go from living in water, breathing through gills to living on the ground, breathing through lungs. The metamorphosis of the European common frog lasts 16 weeks. During this period, anurans go through the stages of egg, embryo or larva, tadpole, two-legged tadpole, four-legged tadpole and adult. This infographic from the Ábaco collection belongs to the Amphibians and Fish series, which also includes those originally titled: What Is an Amphibian?, Fish Anatomy, Bony Fish and Cartilaginous.