From frog's spawn to tadpoles to frogs
Below is the life-cycle of the common frog. The Latin name for this frog is Rana temporaria. The life-cycle of the American bullfrog (Latin name: Lithobates catesbeiana) is very similar. Click here for a picture of the American bullfrog.
Mum and dad frogs go to ponds in the winter. This picture shows how they mate in spring and the mum lays big clumps of eggs.
Frogs eggs are called frogs spawn. Each round black egg 1 mm across sits in a blob of jelly. Click here to see toad spawn.
After a few days the eggs grow into tiny tadpoles inside the jelly.
Then the tadpoles hatch. They are about 5 mm long and can’t swim. They can bend their body from side to side.
When the tail is big enough, they swim off into the pond to start to feed. At first they have gills so can breath under water like fish. Young tadpoles feed by scraping the surface of pond weeds and also eating tiny floating plants called algae. Click here to play a tadpole feeding game called Taddypole!
Later they develop lungs and swim up to the surface to breath. The gills are absorbed and eyes develop. Older tadpoles are then able to feed on small animals like young insects.
The next stage in development is to grow back legs. Tadpoles like the one below need to eat meat at this stage, so if you are looking after them, be careful as they will eat each other if you do not give them meat! Click here to learn how to look after tadpoles as pets.
Finally, tadpoles grow front legs and the tail shrinks and nearly disappears. This is when they move to the side of the pond and climb out onto dry land. A small frog like the one below is called a froglet.
The little froglets will stay by the pond for some time and slowly grow over the summer, eating small insects and worms. They will hibernate just like other adult frogs in damp places near ponds from autumn until the next spring.
The new frogs will become adults ready to mate after four years and will begin the cycle again. Below is an adult female common frog.
Click here or on the link below to print a life-cycle diary to fill out as your tadpoles grow:
Click here or on the link below to print a frog colour-in activity:
Watch this amazing video by Nature North of Wood Frogs developing into froglets in just 7 weeks.
Watch the Singing Zoologist perform his frog life-cycle song “Metamorphosis”. Or click here to visit the website for more info.
Click below to watch an animation of a frog life-cycle in an Australian wetland from Life for Beginners. Or click here to find out more or download the animation.
Media credits: frogs mating- Piet Spaans; Two tadpoles Markus@Thinkaholic; woodfrog with back legs-NatureNorth; froglet-Carols Cornwall.