Amphibians are a group of cold-blooded animals that belong to the class called Amphibia. These animals are characterized by their scale-less, moist skin and their ability to live in water and on land.
These animals represent a vital evolutionary step between land-dwelling reptiles, mammals, and water-dwelling fish.
Amphibians are mainly ectothermic animals divided into frogs, salamanders, and caecilians.
All of these creatures have some interesting features and adaptations. So, in this article, let us discuss some really amazing facts about these animals called amphibians.
Interesting Amphibian Facts
The name amphibian is derived from ‘amphibious.’
The name ‘amphibian’ is derived from the Greek word ‘amphibious,’ which means ‘living a double life.’
This meaning reflects the dual life strategy of these animal species, as most of them can live in water and on land. However, some amphibians are permanent land dwellers, whereas some can live as aquatic animals.
Amphibians are one of the oldest vertebrates.
Amphibians are some of the oldest vertebrates on Earth. These interesting animal species have been around for over 360 million years, making them some of the oldest vertebrates on Earth.
The first amphibians evolved from fish during the Devonian period, which was about 400 million years ago.
Amphibians can be seen on every continent except Antarctica. These are the most diverse animals in tropical regions; however, they can also be found in temperate and even arctic regions.
There are more than 7000 species of amphibians.
Amphibians are diverse groups of animals, with more than 7000 species. This makes them the third-largest class of vertebrates after fish and birds.
The majority of amphibians are toads and frogs, with about 6000 species.
Amphibians need to live near water.
The word “amphibian” means “both kinds of life,” which pretty much talks about these unique creatures.
These animals need to lay their eggs in the water and even need a steady moisture supply to live properly.
Actually, amphibians are perched midway on the evolution tree between fish, which live in water, and mammals and reptiles, which live mostly on land.
Thus, amphibians must stay near water or damp places, like bogs, streams, forests, swamps, rainforests, and meadows.
There are three major categories of amphibians.
Amphibians are divided into three main families: toads and frogs; newts and salamanders; and the worm-like, strange, limbless vertebrates known as caecilians.
Today, there are almost 6000 species of toads and frogs worldwide; however, only one-tenth as many salamanders and newts, and even fewer caecilians.
Almost all living amphibians can be classified as lissamphibians or smooth-skinned; however, there are also some extinct amphibian families, like temnospondyls and lepospondyls as well.
Amphibians are ectothermic
Amphibians are ectothermic animals, meaning they depend on external sources of heat to regulate the temperature of their body.
These animals are often called “cold-blooded” animals, as their body temperature fluctuates with the changing temperature of their environment.
Amphibians can breathe through their skin.
Unlike birds and mammals, amphibians do not have lungs. Instead, they can breathe through their skin, which is incredibly thin and permeable to gases.
This is the reason why amphibians must live in moist environments, and they cannot breathe if their skin dries out.
However, some amphibians have evolved lungs. For instance, salamanders have lungs but can also absorb oxygen through the skin.
Most amphibians undergo Metamorphosis.
Due to their specific position in the evolution tree, these vertebrates hatch from eggs laid in water and briefly follow a fully marine lifestyle, which can be completed with external gills.
The larvae then undergo a specific metamorphosis in which they shed their gills, lose their tails, develop primitive lungs, grow sturdy legs, and, finally, they can scramble up onto dry land.
This larval stage can be seen in frogs as tadpoles and other amphibians, like salamanders, newts, and even caecilians.
Millions of years ago, they ruled the Earth.
For around 100 million years, amphibians were the dominant terrestrial creatures on Earth.
After that, they lost pride of place to different reptile families that evolved from isolated populations of amphibians, including therapsids that evolved into mammals and archosaurs that finally evolved into dinosaurs.
A famous temnospondyl amphibian was the large-headed Eryops, almost two meters from head to tail and weighing about 90 kilograms or 200 pounds.
Amphibians are descended from Lobe-finned fish.
Almost 400 million years ago, a lobe-finned fish ventured onto dry land, with many others on numerous occasions, and went to produce their descendants that are still breathing today.
These ancient tetrapods set the path for later vertebrate evolution with their five-toed feet and four limbs. Many populations went over for millions of years to create the first primitive amphibians, like Crassigyrinus and Eucritta.
Amphibians have permeable skin.
Part of the cause behind amphibians’ need to stay near or in water bodies is that they have water-permeable, thin skin, and hence, if these animals ventured too far from those water bodies, they would eventually dry up and die.
Also, to keep their skin soft and moist, these creatures must continuously secret mucous. Their dermis has glands that can produce noxious chemicals and even deter predators.
In most species, these toxins are not noticeable often, but some frogs can be significantly poisonous to kill even an adult human.
Amphibians have incredibly primitive lungs.
As most body parts of amphibians progressed or evolved greatly, their lungs are still extremely primitive.
Due to this, amphibians are placed near the bottom of the oxygen-breathing ladder. The lungs of these animals have an incredibly low internal volume and cannot process as much as the lungs of mammals and reptiles.
Amphibians can absorb oxygen of limited amounts through their permeable skin, with which they can barely fulfill their metabolic requirements.
Amphibians swallow their prey whole.
Unlike mammals and reptiles, amphibians cannot chew their food. Also, they are poorly equipped dentally.
They only have several primitive “vomerine teeth” in front of the upper part of their jaws that let them hold onto their wriggling prey.
Thus, to compensate for this deficit, most amphibians have sticky, long tongues that can flick out at lightning speeds to snag their meals.
Also, some species even indulge in “inertial feeding” just by clumsily jerking their heads forward and can slowly stuff prey toward the back portion of their mouth.
Amphibians have a three-chambered heart.
Amphibians have a three-chambered heart, which is less efficient than the four-chambered hearts of birds and mammals.
This is because these animals’ deoxygenated and oxygenated blood mixes in the heart, limiting the amount of oxygen that can reach the body.
Moreover, some kinds of amphibians can regenerate their body parts, such as salamanders. For instance, if a salamander loses a limb, it can grow a new one.
Amphibians are among the endangered creatures.
With their dependence on water bodies or moist areas, small size, and permeable skins, amphibians are more vulnerable than many other animal species to critical endangerment and extinction.
It is believed that a good part of all the world’s amphibian species is threatened by habitat destruction, pollution, the ozone layer’s erosion, and invasive species.
Also, a great threat to salamanders, frogs, and caecilians is the chytrid fungus, which some experts think is linked to global warming.
The longest-lived salamander
The olm, or “the human fish,” a small cave salamander, has broken the record for the world’s longest-lived amphibian, as this salamander has a more than 100 years lifespan.
This specific amphibian has a far longer lifespan than any other type of amphibian. However, scientists do not know what the reason behind it is.
Some amphibians have a short lifespan of only one or two years, such as frogs and lizards.
Amphibians are predatory animals.
Amphibians are mainly predatory animals. These animals must consume live invertebrates and those creatures that cannot move too quickly. Some of their foods include earthworms, crayfish, caterpillars, snails, water beetles, and dragonfly larvae.
Moreover, amphibians can be camouflaged in green and brown, their main defense. With this defense mechanism, they can blend in with their surroundings and avoid predators.
Amphibians have different types of reproductive strategies
Amphibians have different types of reproductive strategies. Some can lay eggs in water, while others may lay eggs on land. On the other hand, some can even give birth to live young.
Also, some amphibians can fertilize internally, while others can fertilize their eggs externally.
Some of them have vocal sacs.
Some kinds of amphibians, like toads and frogs, have vocal sacs, which are used to amplify their calls. These calls are used to defend territory and attract mates.
Also, some amphibians can hibernate. During the winter months, they hibernate; hence, their metabolism slows down at that time, and they can survive on stored energy until the arrival of the warmer spring months.
Some of them have adapted to life in extreme environments
Some amphibians have adapted to life in different extreme environments, like mountains, deserts, and caves.
For instance, the Mexican walking fish, called axolotl, can regenerate its organs and live for months without food.
Some kinds of amphibians are a great indicator of environmental health, as they are sensitive to changes in their environment.
Thus, Amphibians are an interesting group of animals that play a vital role in our ecosystems and astonish many animal lovers.
At the end of this article, we learned about 20 really amazing facts about these fascinating creatures called amphibians.
These facts offer us a clear picture of these interesting creatures and their adaptations. If you want to collect some more amazing facts, you may visit our website.
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