What Are The Differences Between Mammals And Amphibians?


As mammals and amphibians are both animals and part of the kingdom Animalia, there are similarities between them. There are also many differences between the two.

Mammals give birth to live young whereas the birth of amphibians takes place externally. Mammals are warm-blooded while amphibians are cold-blooded. Mammals are able to live in all habitats unlike amphibians and have muted colors. Some amphibians can regenerate their limbs.

If you want to read more about the differences and the similarities between both groups of animals then please read on.

There are lots of classes of animals in the natural world and one that is often overlooked is the amphibian. They are a strange class made up of newts, frogs, toads, and salamanders.

Some may mistake them for reptiles because their appearance has some similarities with lizards. But, they are a class all of their own. So what similarities do mammals share with these creatures, if any? What clever adaptations and differences set mammals and amphibians apart? 

What Are The Similarities Between Mammals And Amphibians?

Vertebrates 

Mammals and amphibians are both vertebrates. This means that they both have a similar skeletal system with a backbone and a central nervous system. 

Bison

By comparison, insects, mollusks, and arthropods are invertebrates because there is no backbone. While this might come as a surprise when you see something like a newt swimming around in a pond, they have spines with tiny vertebrae, just like us. 

Breathing

Amphibians are semi-aquatic and can survive for short periods on land out of the water. They do so by breathing air into their lungs as a mammal does.  

Amphibians are also able to take in oxygen and water through their skin because it is much more porous. If amphibians were to stay out of the water for too long, they would suffer from dehydration. 

Hibernation

Many amphibians hibernate to survive the cold winter. This is something that you also see with some mammals that live in colder climates and is a common survival strategy. There are, however, some differences in the details. 

Not all mammals shut down in a deep torpor in the same way as amphibians. Some mammals will periodically wake. Mammals will also build up fat reserves and larders to help them through the winter. 

The metabolism of frogs, toads, and newts can shut down significantly during this time. They just need to be sure that they are in the right conditions. Terrestrial frogs should be safe in burrows but aquatic frogs need to be in contact with oxygen-rich water as they hibernate in the mud. 

From there, there are a lot more differences between mammals and amphibians. Some are quite drastic and others a little more subtle.

What Are The Differences Between Mammals And Amphibians?

Development And Birth

One thing that you will see with almost all mammals is that they keep their young inside their reproductive system until it is time to give birth. The length of this pregnancy differs depending on the animals and the complexity of their physiology. 

The embryos develop into fetuses and then are born as baby animals that can survive, with supervision and feeding, and function on their own. 

With amphibians, the process of development takes place externally. Let’s use frogs as an example. Males will fertilize a female’s eggs during mating, which she will then deposit as clumps of spawn. Over time, the embryos develop without any additional influence from the parents. They turn into tadpoles and feed on their own, then into froglets, and they then lose their tails and become mature frogs. 

Again, there are some cases in the mammalian world where animals do things a little differently. 

One such example is the kangaroo which is a marsupial. Here the fetus develops in a pouch on the stomach of the mother where it can gain the nutrients it needs via her. It then grows into a joey and eventually becomes independent enough to leave the pouch, although it can return to it for protection, warmth, feeding, and transportation. 

There is a small group of egg-laying mammals. These monotremes are still mammals even though they don’t give birth to live young in the same way. They still have mammary glands that produce milk and many of the other classic features.

Cold-blooded And Warm-blooded

Another key difference is the fact that mammals are warm-blooded creatures while amphibians are cold-blooded. What this means is that mammals are able to regulate their body so they can stay at around the same temperature all the time. This is something that we do ourselves.

When we are too hot, we head for shade so that the cool external temperature cools our blood. That is why it helps when we put ice on the veins in our wrists. The vessels are so close to the surface that the blood cools and subsequently cools other parts of the body.

Some animals in hot climates have large ears with big surface areas for the same reason. Mammals can also sweat and pant when hot. 

When it is too cold, we can retreat to warmer places to heat up or shiver to generate energy. Animals that have fur often have denser coats in colder climates for insulation too.

Some creatures will also have shorter legs and muzzles and smaller extremities to control blood flow. It is thought that the snub-nosed monkey evolved without its nose to evade frostbite. 

Amphibians are cold-blooded so take on the temperature of the habitat around them. When things get too cold, they can get sluggish and won’t move all that much. This could be a problem if they haven’t eaten in a while. This is one of the reasons for hibernation in winter. Moving to a sunnier spot will warm them up and help them get the energy they need. 

Habitats

One of the obvious traits of mammals is their ability to adapt to almost any environment and climates in the world. We find mammals living in forests, deserts, polar regions and pretty much everywhere in between that is because there are so many different species with such varied adaptations. 

The cold-blooded nature of the amphibians, and their reliance on water, means that they aren’t able to colonize so many habitats and regions. Temperate zones with plenty of freshwater pools offer a great habitat for frogs, toads, and newts. Beavers can play an important part in habitat management for frogs by creating the still pools via their dams. 

Colors 

The colors on the porous skin of amphibians can vary dramatically. While many toads have darker skin to blend in with their surroundings, there are lots of frog species with an array of colors and patterns. 

Some frogs have green coloration with spots to break up their shape. This is important for camouflage against leaves and pondweed. While there are no green mammals, they do often use color for this purpose as they remain hidden in their habitat. 

However, you never see any mammals with brightly colored fur in tones of blue or bright yellow. Their patterns also tend to be more simple. 

By comparison, poison dart frogs in the rainforest are very vivid and stand out really easily. The purpose here is to show predators that they aren’t edible. 

Of course, there always has to be a species that plays by its own rules. The glass frog is a great example because it is transparent on its body. Scientists still debate why this is the case. 

Regenerative Limbs

There are lots of stories about the incredible powers of the salamander. Some people say that they are immune to fire, while others will suggest that they will activity put out fires if they see them. 

Salamander

One fact that is undeniably true about salamanders is that they, like some species of lizard, are able to regenerate limbs and parts of their tail. If they are ever caught by predators or injured, they can detach the tail or limb, leave that wriggling in the predator’s mouth, and flee. A new limb then grows and they can get on with their life as normal. They do so due to macrophage cells, which are incredibly effective in the healing process. 

Another amphibian is the olm. This form of salamander has adapted to live in cave systems in central Europe. Its evolution in these dark spaces means that it has become blind, as it has no use for eyesight. It is also thought that they can live to be as old as 100. 

There are similarities here to mammals such as moles and other subterranean creatures. They too have little use for sight in order to hunt for their food. However, they can’t survive anywhere near as long as an olm. 

Amphibians and mammals may both be vertebrates, but they branch off into very different directions from there. 

The distinction between vertebrates and invertebrates is important when classifying the animal world, but that is just the start when it comes to the differences here. 

It isn’t uncommon to see amphibians and mammals sharing habitats in temperate and tropical zones but they do so with very different traits. The reproductive cycles and regenerative powers are the most striking. The difference in the temperatures of their blood has a more drastic effect on where they live and how they survive the winter. Although mammals and amphibians both have a backbone, there are many differences between them.

Sources

https://www.nationalgeographic.com/science/phenomena/2010/07/20/the-olm-the-blind-cave-salamander-that-lives-to-100/

https://www.livescience.com/34513-how-salamanders-regenerate-lost-limbs.html

https://www.scientificamerican.com/article/how-do-frogs-survive-wint/#:~:text=Hibernating%20aquatic%20frogs%2C%20however%2C%20must,frogs%20normally%20hibernate%20on%20land.&text=And%20yet%20the%20frogs%20do%20not%20die.

https://www.sciencemag.org/news/2018/06/how-bright-colors-help-these-poison-tree-frogs-hide-predators

https://www.britannica.com/animal/glass-frog

http://coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/coldwarm.html#:~:text=Warm%2Dblooded%20creatures%2C%20like%20mammals,bodies%20at%20a%20constant%20temperature.&text=Cold%2Dblooded%20creatures%20take%20on,when%20their%20environment%20is%20cold.

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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