Amphibians are a diverse class of vertebrates that are typically four-limbed and cold-blooded. They consist of three main groups: frogs and toads, salamanders and newts, and caecilians.
One of the characteristics of amphibians is that they are cold-blooded: their body temperatures are regulated by their surrounding temperatures. They are typically found in terrestrial or aquatic water systems. As a result, amphibians spend part of their lives living in water and part of it on land.
What Are Some Examples Of An Amphibian?
Some common examples of amphibians are frogs, salamanders, amphiuma, lepospondyli, and the Pacific giant salamander.
Are Amphibians Cold-Blooded?: What are the Characteristics of Amphibians?
The characteristics of amphibians set them apart from all other living things.
- amphibians are cold-blooded;
- amphibians live on land as well as in the water;
- amphibians lay eggs to reproduce their species (nearly all amphibians lay their eggs in or near water);
- amphibians have moist skin;
- amphibians do not have scales;
- amphibians have webbed feet.
Most adult amphibians are meat eaters. They eat small animals and insects like slugs, snails, worms, and spiders.
These are the characteristics by which all amphibians can be identified. Still, the different species within the set will have other features which set them apart from the others — otherwise, we wouldn’t be able to tell the difference between frogs and toads!
What Is The Life Cycle Of An Amphibian?
- Amphibians’ eggs are laid in a group in the water.
- After 2-25 days, the tadpole hatches from the egg.
- It swims and eats plants. It breathes through the gills.
- The tadpole grows fins and a stronger tail. Then, it develops lungs and hind legs.
- The tadpole grows front legs, and its tail shortens. It uses nutrients in its tail as food. Then, it jumps out of the water onto land.
- The tail disappears, and it starts to eat insects instead of plants. It takes 2-4 years for the young one to become an adult and lay eggs.
Interesting Facts About Amphibians
- There are more than 4000 types of amphibians.
- The word ‘amphibian’ means two lives. First, amphibians typically start as larvae, living in water and breathing through their gills. Then, the young ones undergo metamorphosis to become adults that live on land, breathing with their lungs.
- Amphibians have smooth, moist and permeable skin, allowing some of them to breathe through their skin.
- Millions of years ago, till the end of the Permian period, amphibians were the dominant terrestrial animals.
- Amphibians swallow their prey whole because they have poorly developed dental structures with few teeth. However, they are equipped with long tongues, which help them capture their prey and swallow it whole.
- Some amphibians have glands that produce a poison that they secrete when threatened.
Amphibians: The Three Subgroups
What is a salamander?
Here we shall explore some fun facts about salamanders, their habitat, diet, and life cycle.
Salamanders are a subgroup of amphibians, and there are currently ten different salamander families. You can tell that an amphibian is a salamander by checking its characteristics. They have:
- a lizard-like appearance;
- blunt snouts;
- slim bodies;
- short limbs that come out of the body at a right angle;
- tails when larvae and in adulthood.
One of the oldest surviving descriptions of the salamander was from Pliny the Elder, a Roman author who lived between 23-79 CE. He described them as:
‘An animal like a lizard in shape with a body specked all over; it never comes out except during heavy showers and goes away the moment the weather becomes clear.
Where are they found?
Salamanders mainly live in cool, wet areas of the Northern Hemisphere, where their diversity is at its highest. However, some are found in the tropical forests of Central and South America.
What do salamanders eat?
Salamanders are carnivores, which means that they only eat other animals. They are thought to prefer slow-moving prey because they are easier to catch. These can range from worms, slugs, and snails. More giant salamanders may also eat fish, insects, and small crustaceans.
If food is scarce, then some salamanders result in cannibalism (the eating of one’s species). Salamanders known to do this are tiger salamanders, as they sometimes feed off of each other when at the larvae stage. Blackbelly salamanders are also known to provide on adults or the young of their species.
Salamander life cycle
The salamander life cycle goes like this:
- It starts with the laying of eggs.
- These eggs then grow into larvae (an immature animal that significantly differs from their mature version) with gill buds.
- The larvae then grow forelimbs.
- Then the back limbs are developed.
- And eventually, the larvae grow into the adult version of the salamander.
Salamander Fun Facts
- Their skin is permeable.
- Some salamander species live entirely in the water and on land, and some swap between the two.
- They can regenerate lost limbs- some researchers hope to find out how this takes place so that human injuries such as brain damage can be healed.
- They rarely have more than four toes on their front legs and five on their hinds, but this can vary in some species.
- They typically lay their eggs in water.
- Unlike frogs, salamander larvae have teeth.
- Salamanders move relatively slowly, which makes them seem as though they are easy prey.
- However, their damp, slippery skin makes them more challenging to catch.
- When attacked, salamanders will often turn their poisonous glands toward the predator. These are usually found on the tail.
Salamanders in folklore
Over the centuries, many real creatures have been given mythical, spiritual, and magical properties in literature and folklore; this was often done outside mainstream religion, and it could have encouraged some people to believe that the actual creature possessed these mythical traits. Salamanders are no exception to this and have been ascribed different fictional characteristics over the centuries.
In folklore, salamanders have been described according to how they look in their basic form- with their lizard-like bodies. They have also been told to have an association with fire. However, a Roman author, Pliny the Elder, also said salamanders could put out fire, describing them as much more toxic than they are.
These ideas are untrue, and some writers have proposed that a salamander could withstand high temperatures and put out fires down to the milky substance they produce when frightened, which makes their skin moist.
What is a frog?
Here we shall explore some fun facts about frogs, their habitat, diet, and the frog life cycle.
Frogs are another subgroup of amphibians that can be recognized by their slimy skin, bulging eyes, and croaking call. There are over 6,000 species of frogs, making them one of the most diverse animal groups in the world. Their vast population means frogs massively outnumber the other subgroups of amphibians — salamanders and caecilians.
Some of the frog’s most defining features are:
- Slimy skin
- Bulging eyes
- Strong hind legs for jumping
- Webbed feet for swimming
While we don’t typically think of frogs as dangerous animals, some species are highly toxic. Poisonous frogs can be identified by their brightly colored skin, which is used to ward off predators. Some poisonous frogs are so toxic that a single drop of their skin secretions is enough to kill an adult human. Frogs that aren’t poisonous tend to have less brightly colored skin designed to help them camouflage into their surroundings; this is a survival technique so that they can hide from predators.
Given that there are over 6,000 species, there are many different sizes of frogs. For example, the Goliath frog is the most giant frog that measures around 30 centimeters in length and weighs about 3 kilograms. In contrast, the smallest frog in the world is called the gold frog. The gold frog is just 1 centimeter long and weighs around 200 grams.
Where are they found?
Frogs require water to reproduce, so you will typically find them in areas with easy access to water. However, aside from this one requirement, frogs can live anywhere. Frogs can live in almost every environment, which is why they can be found on every continent in the world, apart from Antarctica. For instance, some frogs enjoy super hot, humid environments, like the poison dart frog, which resides in the tropical forests of Central and South America. At the same time, some frogs prefer to live in colder, wetter environments, such as the leopard frogs, which live in the marshes and grasslands of North America. Contrastingly, some species of frogs thrive in arid conditions, like the desert frog, which can only be found in Namibia and South Africa, along the coast in dunes.
What do frogs eat?
When it comes to their diet, frogs are certainly not picky eaters. They will eat pretty much anything that they can get their hands on. Their diet typically includes a lot of:
- Bugs
- Spiders
- Worms
- Slugs
- Larvae
- Small fish
Frogs can catch their food using their long, sticky tongues. First, they stay quiet and super still until their prey is close enough to notice, then they shoot out their tongues and pull the prey into their mouths. This movement is unbelievably fast, so their prey has no time to even think of escaping. Frogs can snap their tongues back into their mouths within 15/100ths of a second.
Insects make up a considerable part of frogs’ diet. So without frogs, the world’s population of insects would likely get out of control.
Frog life cycle
Frogs grow up fast; from the moment they are born, it takes 14 weeks to develop into fully grown adults.
The life cycle of a frog is similar to that of a butterfly, as they both undergo metamorphosis. Metamorphosis is the transformation that happens as frogs change from eggs to tadpoles to fully grown frogs.
Here is a rundown of each stage in the life cycle of a frog:
Stage 1: Eggs
Unlike humans, who typically have just one baby at a time, frogs lay hundreds of eggs, which clump together in groups known as frogspawn. Frogs lay these tiny eggs in early spring, as the weather begins to warm up.
You can find frogspawn in shallow, still water, like a pond, or in the reeds at the edge of a stream. Unfortunately, the tiny frogspawn has no way of defending themselves against predators, so they take shelter amongst vegetation and live just below the water’s surface for protection.
Frogspawn has a very distinct look. It is a large, jelly-like cluster of minuscule, circular eggs, each with a tiny black dot in the middle. Over time, the shape of these little eggs begins to change into more of a ‘comma’ shape as their tails develop.
Stage 2: Tadpoles
Frogs spend around 1 to 3 weeks as an egg before hatching into a baby frog. Baby frogs are known as tadpoles. While they are not yet fully developed, tadpoles have gills, a mouth, and a long tail, which they can use for swimming.
This stage in the life cycle of a frog is also known as the larval stage because tadpoles are frog larvae.
They remain pretty still for the first couple of weeks after tadpoles have hatched because they are still absorbing nutrients from the yolk of their egg. However, once the yolk is gone, the tadpoles are strong enough to start moving around and exploring their habitat.
At this stage, tadpoles must stay in the water, as they can’t yet travel on land. Therefore, a tadpole’s diet consists of things they can find in the water; this includes a lot of plant material that has been filtered from the water and chunks of nearby vegetation.
Over 14 weeks, tadpoles undergo metamorphosis, slowly transforming into frogs; this involves growing legs. The hind legs are the first to grow; the front legs come in. After this, their body develops, enabling them to consume things like insects. The next step is for the tadpoles’ signature tail to shrink away and for their gills to be replaced by a layer of skin. Fully grown frogs do not need gills, as they develop lungs for breathing. It is at this stage that tadpoles also begin to grow eardrums. These steps are vital for allowing tadpoles to exist on land.
Once tadpoles have lost their gills and tails, they undergo a 24-hour period in which the remaining part of their metamorphosis occurs. After this is complete, the tadpoles are fully transformed into frogs.
A fascinating fact about tadpoles is that they can control the timing of their transformation. For instance, tadpoles can metamorphose faster if they live in a hazardous environment. In this situation, tadpoles will be vulnerable in the water, so they will want to transform into adult frogs to escape to the land. On the flip side, if tadpoles live in a super-rich environment with lots of plants to eat and very few predators, they can delay their metamorphosis. Tadpoles can also do this if their environment is frigid. When waiting for their transformation, tadpoles can stay in the water for up to a year.
Stage 3: Adult Frogs
At this stage in the life cycle, frogs are fully grown. Part of being an adult frog is that they are much less dependent on water and tend to spend most of their time on land. Frogs do need to maintain their moisture, however, which they do by sticking to shaded areas. Therefore, frogs can dry out completely if they spend too much time in the sun.
Female frogs will return to the water during reproduction to lay their eggs. This step completes the life cycle of a frog.
Frog Fun Facts
- There are more than 6,000 species of frogs in the world.
- Frogs need a lot of moisture but take water through their skin instead of drinking it.
- Each species of frog has its unique call.
- Some frog calls are so loud that they can be heard from up to a mile away.
- Frogs are famous for their incredible jumping skills. Some frogs can jump over 20 times the length of their bodies.
- The health of frogs is a superb biological indicator of the health of ecosystems.
- The word ‘amphibian’ derives from a Greek word meaning both lives because frogs have two lives: life in the water and life on land.
Frogs in folklore
Frogs are depicted as actual figures throughout a variety of different cultures. They also appear in a lot of folklore and fairy tales. Many famous examples include Kermit the Frog from The Muppets and Mr. Toad from The Wind in the Willows.
In terms of their cultural significance, frogs played an essential role in Ancient Egypt and Mesopotamia. In these cultures, frogs were regarded as a symbol of fertility. In Egyptian mythology, a frog-goddess called Herget even represented fertility.
Similarly, the Greeks and Romans viewed frogs as a fertility, harmony, and sensuality symbol.
What is the world’s largest amphibian?
The South China Salamander
Experts think the South China Salamander may be the largest amphibian and the most giant salamander on Earth. It’s from south China and lives mainly around the Pearl River. The largest known specimen of this creature was 1.8 meters long, captured in the early 1920s.
The first South China Salamander was described by an expert called Edward George Boulanger on a specimen kept at London Zoo. It is thought to have come from Guangxi or the Guangdong Province and was most likely one of many creatures to have been taken to the Hong Kong Zoological and Botanical Gardens’ water fountain only to have escaped. The giant salamanders held their run due to a burst pipe in the water fountain, which left a large ditch in the land they fell into. The giant salamanders were fed live tadpoles and sometimes beef at the gardens.
The species is now critically endangered because it was seen as a delicacy for cuisine in China and was used in Chinese medicine. Many are farmed en masse for food and medicine, which causes different species to mix; this has led to the South China Salamander, otherwise known as A. sligoi, being classified as critically endangered. Efforts to conserve wild populations that haven’t been bred with other species for farming or medicine have been proposed as a way to save them.
Is the giant salamander extinct?
The giant salamander is not extinct. It is thought that there are around 50,000 individuals still living in the wild. Many of these are supposed to live in southern and Central China, with groups fragmented around the area. If you’d like to visit a Chinese giant salamander, take a trip to Belfast Zoo and meet Professor Wu, the only Chinese giant salamander in the UK.
How long do giant salamanders live?
The lifespans of different salamanders vary, but it is thought that some could live for up to 70 years, although this has not been recorded.
Who is the oldest living salamander?
In the Artis Zoo in Amsterdam, two Japanese giant salamanders (Andrias japonicus) reached the age of 52 years, which is the oldest documented age for an amphibian, making them the oldest recorded living salamanders.
What is the smallest salamander in the world?
The world’s smallest recorded salamander species is the Thorius arboreus from Mexico. The IUCN (International Union for Conservation of Nature) has classed this species as endangered because its population is declining despite always being rare. These species live in trees in tropical forests, otherwise known as cloud forests. Due to only being adapted to live in this type of environment, they are very vulnerable. Their current main threats are logging and farming.
How can I teach children about amphibians?
Are you interested in teaching your class about amphibians? There are lots of different ways to do this. PowerPoints are a fantastic way to introduce a whole classroom full of children at once. They also have lovely illustrations and break the information into manageable chunks.
Worksheets are a great way to test children’s understanding of a topic. Quizzes are a great hybrid of these two options. You can tailor your questions to the areas of learning your pupils may need to focus on a little more. Make sure to throw in a few easy questions like ‘Are amphibians cold-blooded?’ or ‘Name two different kinds of frog’ too!
You can adapt your lessons to suit pupils’ needs and learning goals. See below for some fantastic resource options you may want to consider when teaching your class about amphibians.
