Fun Frog Facts

Facts about tadpoles, frogs, newts and amphibians!

What are tadpoles?

Wood frog tadpoles

Frogs, toads, newts and salamanders are Amphibians. They all spend part of their life on land but go back to water in ponds, lakes and rivers to lay eggs. The eggs hatch into tadpoles. Young tadpoles are rather like baby fish. They swim by using their tails and use gills to get oxygen from the water. They often feed on plants. The photos of Canadian Wood Frog tadpoles are by NatureNorth.com

When tadpoles get bigger, they develop lungs to breath air, grow legs and  start to eat other small animals.

After a few weeks the tail gradually shrinks and they hop out of the water as tiny froglets. Most adult amphibians, like frogs, eat insects.

Click to see more about the life cycle

What are Amphibians?

There are three types of amphibians:

Anura: 6,642 species of frogs and toads without tails. Many have a tongue they can shoot out to catch insects.

Caudata: 684 species of newts and salamanders with a long tail. This is a Smooth Newt Triturus vulgaris (Photo by Magnus Maske)

Gymnophiona:  205 species of worm-like caecilians,without any legs and living underground mainly in South East Asia (Photo of Dermophis mexicanus by Franco Andreone).

Find out more about UK amphibians here.

The frog as an example

There are huge numbers of different kinds of frogs found all over the world and you can find pictures at AmphibiaWeb, the smallest of which (Paedophryne amauensis) is barely larger than a house fly and the largest (Goliath frog) can weight more than 3 kilograms. They are divided into families with Latin names. One widespread group of frogs has the Latin family name Rana. This is still the word for frog in Spanish and Italian.Here are some examples of this family of frogs from different countries. The tadpoles and life-cycle of all of them is very similar.

The Common Frog in Europe has the family name Rana and its specific name is temporaria (photo by ©Dave Mangham, www.wildlifephotos.org.uk)
The American Bullfrog is bigger and its name is Rana catesbiana (photo by John White).

The Freezing Frog

The Wood Frog (Latin name: Rana sylvatica) in Canada is specially adapted to survive temperatures as cold as 3 degree Fahrenheit (-16 degree Celsius) in winter. It produces its own antifreeze by using urine and glucose inside its blood. Watch the video below to learn more on how amazing the wood frog’s body works in extreme weather.

See-Through Glass Frogs

To survive predation, animals can camouflage if their body skin colour/texture matches the envioronment. Glass frogs live on trees. They need to avoid being eaten by predators from above and below. Their green skin on the back side helps them camouflage when they rest on a leaf when viewed from above while their belly skin is transparent. However, their body silouette could be visible when seen from below the leaf. Glass frogs have a clever trick to hide their body silouette by consealing 90% of their blood while sleeping. check the photo below to see how effective it is:

A pair of mating glassfrogs sleep together on a leaf. © Jesse Delia

The Digestive System

 

The digestive system is modified to account for the change of the herbivorous diet of the tadpole to the carnivorous diet of the frog.

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The Skin

 

The skin adapts for the change from a purely aquatic lifestyle to an amphibious lifestyle.

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The Reproductive System

 

The urogenital system develops to allow for reproduction in adulthood.

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The Skeleton

 

The skeletal structure develops to accommodate the change from tail swimming to using legs to move around. The skull also needs to be remodelled for a frog's change in vision.

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The Nervous System

 

A tadpole sees from eyes that are positioned on opposite sides of the head. During metamorphosis, the optical nerves develop to accommodate a frog's binocular vision, where the eyes are positioned at the front of the head.

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1. Mating and Laying Spawn

 

Male and female frogs go to ponds in the winter. They mate in the spring, and the female lays big clumps of eggs.

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2. Frog Spawn

 

Frogs eggs are called frogspawn. Each round black egg is about 1 mm wide and is surrounded by a blob of jelly. Other animals produce spawn as well, which you can look at here.

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3. Maturing Frog Spawn

 

After a few days, the eggs begin to grow into tiny tadpoles inside the jelly.

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4. Hatchlings

 

Then the tadpoles hatch! They are about 5 mm long and they can’t swim (yet). They can bend their body from side to side using special muscles along their trunks and tails.

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5. Young Tadpoles

 

When their tail is big enough, they swim off into the pond to start to feed. At first they have gills (the pale protrusions from the head region in the left photo) so they can breath underwater like fish. Young tadpoles feed by grazing the surface of pond weeds and also eating tiny floating plants called algae.

Click here to play a tadpole feeding game called Taddypole!

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6. Maturing Tadpoles

 

Later they develop lungs and can swim up to the surface of the water to breath. The gills are absorbed back into their bodies and eyes develop. Older tadpoles are then able to feed on small animals like young insects.

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7. Mature Tadpoles

The next stage in development is to grow back legs. Tadpoles during this stage need to eat meat in order to get the proper nutrients to grow.

If you are looking after tadpoles, be careful as they can eat each other if you don't give them meat to eat! Click here to learn more about how to look after tadpoles as pets.

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8. Froglet

Finally, tadpoles grow front legs and their tail shrinks until it almost disappears. This is when they climb out of the pond and start living on dry land. Small frogs are commonly called froglets.

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9. Adult Frog

The little froglets will stay by the pond and slowly grow over the summer, eating small insects and worms. They will hibernate just like other adult frogs in damp spots near ponds from autumn until the next spring.

After four years, the new frogs will become adults and will be ready to mate and begin the cycle again.

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Copy - 9. Adult Frog

The little froglets will stay by the pond and slowly grow over the summer, eating small insects and worms. They will hibernate just like other adult frogs in damp spots near ponds from autumn until the next spring.

After four years, the new frogs will become adults and will be ready to mate and begin the cycle again.

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