Bullfrogs, which are hatched from eggs, spend their first winter as tadpoles since it takes up to three years to grow into maturity as a bullfrog. One-year-old tadpoles can be up to 6 inches long. Once the tadpole is old enough, it begins to sprout legs that develop on the tadpole's body as they sprout. It then begins to sprout arms in the same fashion, developing on its as they sprout. The froglet, or nearly mature frog, has developed lungs to breathe with to replace its gills. It can hop on land but still has its tail. The mature frog is one that has lost its tail and has a low pitched croak in place of the young frog's high pitched chirping sound.