Frogs breed in water, and tadpoles are born underwater. It has gills and a tail for swimming. As it grows, the tadpole will develop legs, its body and mouth will enlarge, its gills will be covered with skin. Depending on the species, this transformation takes from a few days to several weeks. It is the transition from an aquatic lifestyle to an amphibian lifestyle: the ability to live on land and underwater. Photo credit: Smudge 9000