Amphibians

Amphibians are the class of animals that include salamanders, newts, frogs, toads, and cecilians. Cecilians are a group of legless amphibians that live in tropical parts of the world.

Just like people, amphibians have an internal skeleton made of bone. They also have a heart, stomach, intestines, and kidneys. Due to the similarity between amphibians and humans, high school biology students often learn the internal anatomy of a frog.

Amphibians are ectothermic (cold blooded), so their body temperature is determined by the environment outside of their body.

Amphibians have skin that is either covered in slimy mucous (like salamanders and frogs) or dry and warty (like toads and newts.) Their skin is permeable to air and water - they absorb oxygen directly into their bloodstream through their skin. This is one reason why they are so sensitive to pollution in their environment - they can absorb toxins directly into their body. Scientists often use amphibians to help determine if a habitat has been polluted.

Unlike reptiles or birds, amphibian eggs lack a protective shell. Instead, the eggs are encased in thick, jelly-like mucous. Most amphibians lay their eggs in water, however, a few species such as the red-backed salamander lay their eggs on land.

Most amphibians are born in a larval state and must go through metamorphosis to become an adult. A tadpole which has gills to breathe water like a fish, a tail, and no legs will change or morph into a frog by growing arms and legs, losing it’s tail, and growing lungs to replace the gills.

Imagine what it would be like if YOU had to go through metamorphosis - WEIRD!