A young frog is called a tadpole. Tadpoles are the larval stage of frogs and are typically aquatic, living in water where they undergo metamorphosis. Initially, they possess gills for breathing underwater, long tails for swimming, and no limbs. Over time, they develop legs, lose their tails, and transition to a terrestrial or semi-aquatic adult form known as a frog. This transformation from tadpole to adult frog illustrates the fascinating process of metamorphosis found in many amphibians.