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Frog

life science Maturity 7-9 Next article →

Frogs are amazing members of a huge group of animals. They belong to the order Anura, which means "without tail."

Anoures
Anoures

Most frogs are amphibians, which means they live part of their lives in water and part on land. They are very successful living things. In fact, they make up about 88% of all amphibian species. You can find them in many places, from hot tropical rainforests to cold subarctic regions.

Litoria tyleri
Litoria tyleri

Because they are so diverse, they are one of the five most diverse groups of vertebrates on Earth.

A frog's life involves many changes. Most frogs start as eggs laid in the water.

Frogspawn closeup
Frogspawn closeup

These eggs hatch into tadpoles, which are small creatures that live entirely underwater. Tadpoles have tails and internal gills to help them breathe. Eventually, they go through metamorphosis, a big change in their body shape.

Greenfrog life stages
Greenfrog life stages

During this time, they grow lungs and develop legs. Their tails shrink away into a bone called a urostyle. As adults, they use both lungs and their skin to breathe.

Frog anatomy tags
Frog anatomy tags

Scientists have studied frogs for a very long time. We know that very old "proto-frogs" lived a long time ago. One fossil named Triadobatrachus was found in Madagascar.

Fossilised frog
Fossilised frog

This fossil is from the Early Triassic period, about 250 million years ago. Some scientists think frogs might have even appeared 265 million years ago. In 2008, researchers found a fossil called Gerobatrachus hottoni in Texas.

Fossilised frog
Fossilised frog

This fossil lived 290 million years ago and looks like both a frog and a salamander.

Adult frogs have many interesting physical traits. They usually have stout bodies and eyes that stick out.

Their skin is very special because it is semi-permeable. This means it lets things pass through it. Because of this, frogs must stay in moist places so they do not dry out.

Ranapipiensmoulting
Ranapipiensmoulting

Some frogs have skin that is bright red or yellow. This bright color warns predators that the frog might be toxic. Other frogs have brown or green skin to hide in plants.

WoodFrog DarienLakesStatePark 2020-06-16 (02)
WoodFrog DarienLakesStatePark 2020-06-16 (02)

Frogs play a vital role in the world's food webs. They are low-level consumers that eat many small things.

TrophicWeb
TrophicWeb

Most adults are carnivores that eat insects and other small invertebrates. They catch food by using a long, sticky tongue.

Dendropsophus microcephalus - calling male (Cope, 1886)
Dendropsophus microcephalus - calling male (Cope, 1886)

They are also important food for bigger predators. Because of this, scientists call them environmental bellwethers.

TrophicWeb
TrophicWeb

This means that if frog populations decline, it is an early warning sign that the environment is in trouble.

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🖼️ Images & Media (40)
File:Anoures.jpg
Anoures.jpg
File:Bombina bombina 1 (Marek Szczepanek) tight crop.jpg
Bombina bombina 1 (Marek Szczepanek)...
File:Atelopus zeteki1.jpg
Atelopus zeteki1.jpg
File:Fossilised frog.jpg
Fossilised frog.jpg
File:Frog limbs.jpg
Frog limbs.jpg
File:Rana temporaria 04 by-dpc.jpg
Rana temporaria 04 by-dpc.jpg
File:Litoria tyleri.jpg
Litoria tyleri.jpg
File:Ranapipiensmoulting.jpg
Ranapipiensmoulting.jpg
File:Hip-pocket Frog - Assa darlingtoni.jpg
Hip-pocket Frog - Assa darlingtoni.jpg
File:WoodFrog DarienLakesStatePark 2020-06-16 (02).jpg
WoodFrog DarienLakesStatePark 2020-06-16 (02).jpg
File:Frog anatomy tags.PNG
Frog anatomy tags.PNG
File:Groene kikker achter Bekaert-draad-detail oog.jpg
Groene kikker achter Bekaert-draad-detail oog.jpg

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