The Life Cycle of a Frog

From jelly egg to jumping frog

A frog does not start its life looking anything like a frog! It begins as a tiny egg in a pond, hatches into a wiggly swimmer with a tail, and slowly changes shape until it becomes a hopping, croaking frog. This amazing change is called the life cycle of a frog, and it happens in four main stages. Let's follow it from the very beginning.

Stage 1: The egg (frogspawn)

In spring, adult frogs return to ponds to lay their eggs. A mother frog can lay hundreds, or even thousands, of tiny eggs all at once. The eggs are wrapped in soft, clear jelly, and together they form a cloudy clump called frogspawn. You can often see it floating near the edge of a pond.

If you look closely, each egg has a small black dot in the middle. That black dot is the baby frog beginning to grow. The jelly around it acts like a soft cushion, protecting the egg and helping to keep it safe and warm. Frogs lay so many eggs because many will be eaten by fish and birds, so laying lots gives at least some of them a chance to survive.

Stage 2: The tadpole

After a week or two, the eggs hatch. But the creature that wriggles out does not look like a frog at all! It is a tiny tadpole, with a round head and a long, wiggly tail. It has no legs yet.

At first, the tadpole breathes underwater using gills, just like a fish. It cannot live out of the water at this stage. It swims about eating tiny plants and algae, growing a little bigger every day. Tadpoles are a favourite snack for many pond animals, so they have to be quick to stay safe.

Stage 3: Growing legs (the froglet)

Now the tadpole begins to change in an amazing way. First, two little back legs start to grow. After a while, two front legs appear as well.

While the legs are growing, big changes are happening inside the tadpole's body too. It slowly stops using its gills and grows lungs instead, so it can breathe air, just like you do. At the same time, its long tail starts to shrink. The tadpole's body is changing so it can live on land as well as in the water.

When the creature has four legs but still has a little stump of a tail, we call it a froglet. The froglet can now climb out of the water and breathe air, but it still has more growing to do.

Stage 4: The adult frog

Finally, the tail disappears completely, and the froglet becomes a fully grown adult frog. Now it can hop on land, swim in water, and catch insects with its long, sticky tongue. Adult frogs live near ponds and damp places. The males often croak loudly, especially in spring, to call to other frogs.

When the frog is grown up, it will return to a pond to lay eggs of its own, and the whole life cycle begins all over again.

What is metamorphosis?

The huge change from a swimming, gill-breathing tadpole into a hopping, air-breathing frog is called metamorphosis. It is a special word that means changing body shape as an animal grows up. Frogs are not the only animals that go through metamorphosis. Butterflies do it too, changing from a caterpillar into a beautiful winged insect.

Why do frogs change like this?

Why bother with such a big change? The answer is that it lets a frog use two different worlds. As a tadpole, it can live safely in the water, eating plants and growing fast. As an adult, it can leave the crowded pond, hop onto land, and find new food and new places to live. Changing shape gives the frog the best of both the water and the land.

Go pond dipping

In spring, ask a grown-up to take you to a pond at a park or nature reserve. Look carefully near the still, shallow edges. Can you spot cloudy clumps of frogspawn, or tiny black tadpoles darting about?

If you visit the same pond every week or two, you can watch the life cycle happen in real life. See if you can spot the moment tadpoles begin to grow their back legs. Keep a little nature diary and draw what you see each week. Remember to look but not touch, and never take frogspawn or tadpoles home, as they belong in their pond.

Frogs are not the only creatures that change shape as they grow. Read about another amazing transformation in The Life Cycle of a Butterfly. And to find out who eats tadpoles and what frogs eat, explore Animals and Their Homes.