The common pond frog’s life begins in a quiet pond as one of many jelly-like eggs laid together in a mass by the mother frog.
In a few days, the egg hatched into a tiny, legless tadpole that breathes with gills, as fish do. it has a long tail which it uses for swimming, and eat plants that grow in the water.
As the tadpole grows, first two hind legs and then two front legs appears. After a time the tail begins to shrink and the tadpole loses its gills and gets lungs instead.
Then the tadpole comes to the surfaces of the water to breath air.
At last its tail disappears and the change is complete.
As a young frog, the creature is now ready to leave the water and begin a life as a hoping land animal.
Most tadpole make the change into frogs in the three months of spring. Most toads begin life a tadpole, much like frogs do. – Dick Rogers