Spawn

• Frog eggs, when massed or clumped together, are called spawn. To protect the eggs, frogs lay them all together, usually thousands at a time, in a wet environment such as puddle or a drainage ditch. In some frog species, the females stay with the spawn; in others, they leave after laying the eggs.
  
  

Egg

• Each individual frog begins its life as one egg in the spawn. It starts out as a single cell inside an egg, and then it divides to become two cells, and then four, until an embryo is formed. The embryo feeds on the yolk inside the egg.
  
  

Tadpole

• Approximately 21 days after the egg was laid, a tadpole emerges from the egg. A tadpole looks like a tiny fish without fins. Even after hatching, the tadpole feeds on the yolk that is left in the hatched egg. Tadpoles are very fragile immediately after hatching and have poorly developed gills. After about seven days, the tadpoles start to swim around in their environment and eat algae.
  
  

Tadpole with Legs

• After about six weeks, the tadpole starts to grow legs and its diet becomes more diverse. It starts to feed on small insects. At the nine-week mark, the tadpole starts to develop arms, with the elbows emerging first. Its gills disappear as lungs start to develop.
  
  

Young Frog (Froglet)

• At 12 weeks the tadpole's tail starts to disappear. At this point, the young frog no longer has gills, has a set of arms and legs, and its tail is becoming a nub. The froglet begins spending time out of the water on the land.
  
  

Adult Frog

• A frog is full grown between the ages of 12 and 16 weeks, depending on the water and food supply available at the time.