When we think about animals that change as they grow up, frogs often come to mind first. We all know how tadpoles turn into frogs. But what about salamanders? Do they change in the same way?
Salamanders do not go through complete metamorphosis like some insects do. Instead, they undergo a type of metamorphosis more like frogs, but their transformation is gradual and different from frogs. They develop slowly without a resting pupal stage, and their larvae already look like small adults with gills.
What Is Metamorphosis?
Before we look at salamanders, we need to understand what metamorphosis means. Metamorphosis is when an animal changes from one form to another as it grows up.
These changes are usually big and noticeable. Scientists have found two main types of metamorphosis in nature.
Complete Metamorphosis
Complete metamorphosis happens in four clear stages. First comes the egg. Then the larva hatches out. After that, there is a pupa stage where the animal rests and changes.
Finally, the adult emerges. Butterflies are a good example of this process. They start as eggs, become caterpillars, then form a chrysalis, and finally emerge as butterflies.
Some frogs also go through what looks like complete metamorphosis. Their eggs hatch into tadpoles. These tadpoles look very different from adult frogs.
They have tails and no legs. Over time, they grow legs and lose their tails. However, frogs do not have a true pupa stage like insects do.
Incomplete Metamorphosis
Incomplete metamorphosis is simpler. It has only three stages: egg, nymph, and adult. The nymph looks like a small version of the adult.
As it grows, it gradually becomes more like the adult form. Grasshoppers and dragonflies develop this way.
How Salamanders Grow and Change
Salamanders are amphibians, just like frogs. They belong to a group called Caudata. But salamanders do not change in the same way that frogs do.
Their development is more gradual. Let us look at each stage of their life cycle.
Stage 1: The Egg Stage
Most salamanders begin life in water. Female salamanders lay their eggs in ponds, streams, or other wet places.
Some species lay eggs in clusters. Others lay them one at a time. Each egg is covered with a jelly-like coating. This coating protects the developing baby salamander from harm.
The time it takes for eggs to hatch depends on several things. Temperature plays a big role. Warmer water usually means faster development.
The amount of moisture also matters. Different species take different amounts of time to hatch. Some might hatch in just a few weeks. Others might take several months.
Stage 2: The Larval Stage
When salamander eggs hatch, tiny larvae come out. These larvae live in water. They have gills on the outside of their bodies.
These gills help them breathe underwater. The larvae already have four legs and a tail. This is different from frog tadpoles, which start with no legs at all.
Salamander larvae look like tiny versions of adult salamanders. They are much smaller, of course. They also have those external gills. But their basic body shape is already there. They swim around in the water looking for food. They eat small water creatures like tiny worms and insects.
As the larvae grow, they get bigger and stronger. They continue to live in water during this stage. The length of the larval stage varies by species.
Some larvae might stay in this stage for just a few months. Others might remain larvae for several years.
Stage 3: The Juvenile Stage
As larvae continue to grow, they start to change. The most important change is in how they breathe. Their external gills begin to disappear. At the same time, they develop lungs inside their bodies. This allows them to breathe air.
Some species of salamanders leave the water at this point. They move onto land and begin living a terrestrial life.
Others stay in the water but can now come to the surface to breathe air. Still others can live both in water and on land.
Unlike insects, salamanders do not have a resting stage during this change. There is no pupa stage where they stop moving and eating. Instead, the changes happen gradually while they continue their normal activities.
The juvenile salamanders keep their tails. They also keep their four legs. Their body shape stays basically the same. The main differences are that they get bigger and change how they breathe.
Stage 4: Adult Salamanders
After months or years, salamanders reach adult size. Adult salamanders have fully developed lungs. They can breathe air easily.
They can also absorb oxygen through their skin. This helps them stay underwater for longer periods.
Adult salamanders often return to water when it is time to breed. They lay their eggs in the same types of places where they started life. But during the rest of the year, they might live on land, in water, or both.
Different species have different lifespans. Some salamanders live only a few years. Others can live for more than ten years. A few species can live even longer than that.
How Salamanders Differ from Frogs
The way salamanders develop is quite different from how frogs develop. Understanding these differences helps us see why salamanders are unique.
Physical Changes
Frogs go through dramatic physical changes. Tadpoles have tails but no legs. As they grow, they develop legs and their tails disappear.
Their mouths change shape. Their digestive systems change too. The final adult frog looks very different from the tadpole it once was.
Salamanders change much less dramatically. Larvae already have the basic adult body shape. They have four legs and a tail from the beginning.
They keep these features throughout their lives. The main change is losing their external gills and developing lungs.
Environmental Needs
Most frogs need water to reproduce. Their eggs and tadpoles must live in water. Adult frogs might live on land, but they return to water for breeding.
Salamanders are more flexible. While many species do breed in water, others have adapted to life on land. Some species lay their eggs on land in moist places.
The young hatch as tiny versions of adults and never go through an aquatic stage.
Speed of Change
Frog metamorphosis often happens relatively quickly. Once a tadpole starts growing legs, the transformation to adult form usually takes just a few weeks or months.
Salamander development is more gradual. The changes happen slowly over a longer period. There is no sudden transformation. Instead, the salamander gradually develops from one stage to the next.
The Amazing Variety of Salamanders
There are about 700 different species of salamanders in the world. They live in many different environments.
Some live in forests. Others live in wetlands. Some live in mountains. A few even live in caves. This variety means that salamanders have developed many different life strategies.
Terrestrial Species
Some salamanders have adapted to life on land. The Eastern Red-Backed Salamander is one example.
These salamanders lay their eggs on land in moist places. When the young hatch, they look like tiny adults. They never go through an aquatic larval stage at all.
This adaptation allows these salamanders to live in places where there is no permanent water. They can survive in forests far from ponds or streams.
They get the moisture they need from the environment and their food.
Aquatic Species
Other salamanders remain aquatic throughout their lives. The most famous example is the axolotl. Axolotls never leave their larval form.
They keep their external gills and stay in water their whole lives. But they can still reproduce and have offspring.
This condition is called neoteny. It means keeping juvenile characteristics into adulthood. The Tiger Salamander sometimes shows this trait too
. Some individuals remain aquatic and keep their larval features even as adults.
Flexible Species
Many salamanders can adapt to different conditions. They might live in water as larvae and on land as adults. Or they might move between water and land throughout their lives. This flexibility helps them survive in changing environments.
Conclusion
Salamanders do go through metamorphosis, but their transformation is different from what we see in frogs.
Instead of dramatic changes, salamanders develop gradually. They do not have a pupal stage. Their larvae already look like small adults with gills.
Hi, my name is Ezra Mushala, i have been interested animals all my life. I am the main author and editor here at snakeinformer.com.