Amphibians facts - Classification of Amphibians, Amphibians definition, characteristics and behaviour

 Amphibians - Double life

Amphibians are cold-blooded animals (adjust their body temperature in respect with the surrounding). Though amphibians are similar to reptiles they are separated taxonomically but grouped together as Herpetology in branch of zoology. The amphibian meaning is derived from the Greek word called "amphibios" which means to live or living a double life (both lives) as they live both in water and on land. All amphibians begin their life in water with gills and tails later they develop lungs and legs to live on land. Amphibians are vertebrates (animals with backbone).

Amphibian - Metamorphosis 

Amphibian lays eggs; the eggs have no shells and are laid as jelly like clusters which is called spawns that require a moist environment to survive. Tadpoles or larva hatches from these eggs with limbs like salamanders or without limbs like frogs that later develops. Initially they live in water with gills and tails later as they grow they develop legs, lungs while frogs and toads lose their tails. This process of amphibian growth from egg, larva (with gills) to adult (air breathing) is called Metamorphosis, an Amphibian life cycle. Axolotl is a kind of salamander that stays larva for their entire life with gills and tail in water. These axolotls are threatened by habitat loss. 

Amphibian Classification

Amphibian Species

Amphibians are classified into three groups or orders which are as follows;

1. The first group that includes frogs and toads is called Anura (meaning "without tail"). It is the largest amphibian group that consists of about 6200 species.They have long hind legs and live near freshwater and feed on insects and other small animals. 

2. The second group that includes newts and salamanders is called Caudata (meaning "tail"). They include about 650 species. Salamanders are the only group of vertebrates that has the ability to regenerate lost body parts and even whole limbs. They usually feed on insects and worms and adults spend most of their time on land. 

3. The third group is called Gymnophiona that includes Caecilians. There are nearly 190 species and they look like eels or large earthworms that are found in the tropical regions. They are blind, legless amphibians that feed on worms.

Amphibians facts

1. Though amphibians can live on land, they have skin which is water-permeable and has to stay wet in order for them to absorb oxygen, thus requiring constant supply of water or moisture to prevent from drying which can lead to their death.   

2. Amphibians keep their skin moist by secreting slimy fluid called mucous because they breathe through their skin as well as their lungs. 

3. Amphibians have webbed feet. Amphibian skin is smooth, slimy and moist. They cannot live in salt water, they also do not need to drink water because they absorb it through their skin.

4. Amphibians are largely inhabited near or in water or moistened areas such as streams, lakes, ponds, meadows, bogs, swamps and rain forests. 

5. Frogs such as poison dart frogs are brightly colored that secrete lipophilic alkaloid toxins such as allopumiliotoxin 267A, batrachotoxin, epibatidine, histrionicotoxin, and pumiliotoxin 251D through their skin. It is said that The golden poison frog can kill 10 to 20 fully grown humans with its poison. 

6. There are nearly more than 7,000 species of living amphibians are known. Amphibians list has about 6200 species of Anura, 650 species of Caudata and 190 species of Gymnophiona. 

7. Amphibians can smell. They have sticky end tongue to catch prey; though they have teeth they swallow their food or prey whole. Amphibians are carnivores that feed on bugs, ants or termites, spiders, beetle, slugs, small fish, snails, other frogs, worms, mice, birds and even bats. The Brazilian Tree frog eats fruits and berries which is the only frog that is vegetarian. 

8. Amphibians occur widely throughout the world but are absent in Antarctica. Amphibians hibernate at the cold winter climate. 

9. The largest amphibian is the Chinese Giant Salamander and the smallest amphibian is a frog called the paedophryne amauensis.  

10. Amphibians life span differs in wild and captivity. They live up to 10 to 30 years in wild and live up to 50 years in captivity, while blind Salamanders are predicted to live up to 100 years.

11. The existence of Amphibians are threatened by factors like pollution of freshwater, habitat destruction, invasive species, Global Warming, increased ultraviolet radiation due to ozone depletion. Rapid decline of amphibians is a serious global threat that should be prevented.