Are Turtles Reptiles, Amphibians, Or Mammals? (Explained In Detail)

Image of a turtle swimming inside a sea

Sometimes it is difficult to know if a particular animal is a reptile, amphibian, or mammal. So what about turtles? Are turtles reptiles, amphibians, or mammals?

Turtles are reptiles. They’re cold-blooded, air-breathing, egg-laying animals that have scales. These are the main characteristics of reptiles. Turtles cannot breathe underwater, so they cannot be classified as amphibians. Also, turtles lay eggs to reproduce, so they cannot be classified as mammals.

Besides the points above, reptiles, amphibians, and mammals differ in a few other ways as well. Let’s go through those characteristics in the table below.

What’s The Difference Between Reptiles, Amphibians, And Mammals?

Given below are the main characteristic traits of reptiles, amphibians, and mammals.

ReptilesAmphibiansMammals
Cold-bloodedCold-bloodedWarm-blooded
Have Scales that shedHave Soft skin which is often moistHave fur or hair
Most have clawsDon’t have clawsMost have claws
Lay eggs with hard shells on dry landEggs are released and hatched in water and have membranes instead of hard shellsGive “live birth” to offspring
Produce offspring that have lungsOffspring can have gills in the larval stageOffspring are born with lungs
Don’t feed and nurture their babiesDon’t feed and nurture their babiesMostly feed their young milk from their teats
Don’t need a wet environment to surviveNeed a wet environment to surviveDon’t need a wet environment to survive


Are Reptiles Closer To Mammals Or Amphibians?

This is subjective, but reptiles are closer to mammals than amphibians because of the following reasons:

  • Reptiles and mammals both have lungs and breathe air for oxygen from birth to adulthood. Amphibians start off with gills and breathe underwater.
  • Most reptiles and mammals have claws, while amphibians ordinarily don’t have claws.
  • Both reptiles and mammals start their life on dry land, amphibians start their life in water.
  • Reptiles and mammals don’t go through a metamorphosis phase as amphibians do.

However, although reptiles, mammals, and even amphibians all have some common features, they’re all very different from each other in the grand scheme of things. This is most easily observed in their different lifecycles.

Recommended Further Reading:

Lifecycles Of Amphibians And Mammals Compared To Turtles (Reptiles)

Let’s now see how the lifecycles of amphibians and mammals compare to turtles, which are reptiles.

Amphibians

Amphibians go through a process that starts with an egg covered in a membrane and not a hard shell. Amphibian eggs are laid in water and don’t survive in the open air. This makes amphibians viviparous as their embryos develop within eggs.

Once these eggs hatch, they’ll release small amphibian babies called tadpoles that can breathe underwater with the help of tiny gills.

This is the larval stage, at which time the babies don’t resemble their parents at all. Most of these larvae won’t survive through to adulthood as they’re eaten by other water-dwelling creatures. They will also die from a range of different diseases.

After the larval stage of life, amphibians will start to grow lungs and visit the surface of the water for oxygen. It’s at this stage that their diet also changes from submerged vegetation to small invertebrates, making them carnivorous.

Mammals

Mammals, unlike amphibians and reptiles, are not born from an egg. They’re developed as embryos inside a mother’s body. This makes mammals ovoviviparous. When the fetus is ready for the outside world, the mother will push the baby out and start to nurture it with her breast milk. Amphibians and reptiles don’t produce milk and also don’t look after their babies once they hatch.

Baby mammals look like miniature versions of their parents and only transform in terms of their size as they grow up. On the other hand, amphibians completely change from birth to adulthood.

Reptiles

Unlike amphibians, reptiles lay their eggs on dry land for them to hatch. The eggs, therefore, have hard shells to protect them during the incubation stage. The hatchlings will look like miniature versions of their mother.

Reptiles are born with lungs to breathe air and never have the ability to breathe underwater as young amphibians do.

Similar to amphibians, reptiles will also not look after their young once they’ve hatched. They are fully equipped to look after themselves at that point.

So…

Why Are Turtles Not Mammals?

Turtles are certainly not mammals as they don’t give “live birth” to their young. They also don’t feed their babies milk from their teats as mammals do.

Mammals have hair and/or fluff on their bodies, while turtles have scales.

Mammals are also warm-blooded, unlike cold-blooded turtles. That doesn’t mean a reptile’s blood is literally cold. It just means that its blood is heated up by external factors like the sun and not by any metabolic process like mammals.

So, a turtle is definitely a reptile considering the information above, but does the same go for sea-turtles?

It’s a fair question considering the fact that they can swim under the water for around 7 hours before needing to come up for a breath of fresh air. Sea turtles spend most of their lives underwater except when they come out to lay eggs on dry land.

Let’s look at the relationship between sea turtles and amphibians in a bit more detail.

Related Further Reading:

Are Sea Turtles Amphibians Or Reptiles?

Sea turtles are reptiles, just like other turtles and tortoises, but there are reasons why people may think otherwise.

Like amphibians, sea turtles rely on being in and around water most of the time for survival. This is because they’ve adapted to eat, mate, and evade predators within the water. Therefore, they won’t survive very long on dry land without human intervention. This is what leads some people to wonder whether or not they’re amphibians.

All this being said, sea turtles are still reptiles because they lay their eggs on dry land, they have scales, are cold-blooded,and produce offspring with lungs, not gills. Their eggs have hard shells suited for dry land, unlike amphibian eggs that are comprised of a soft jelly-like membrane suited for hatching underwater.

What’s The Difference Between A Sea Turtle And A Freshwater Turtle?

  • One of the biggest differences between sea turtles and freshwater turtles is the fact that sea turtles can’t retract their heads and limbs into their shells for protection.
  • Sea turtles are faster in the water than freshwater turtles. (Up to 22 mph in some cases)
  • Sea turtles outswim predators as opposed to hiding away from them within their shells.
  • Sea turtles spend most of their time underwater except for when they come out to lay their eggs. Freshwater turtles don’t spend as much time underwater as sea turtles, and they regularly surface to bask in the sun for warmth.
  • Another difference between sea turtles and freshwater turtles is that sea turtles can hold their breath underwater for around twice the amount of time compared to their freshwater counterparts.
  • Sea turtles can plunge to extreme depths underwater and still handle the pressure. Some sea turtles can reach depths of 3000 ft in the ocean. Freshwater turtles aren’t able to do this.
  • Sea turtles have no problem living in the ocean’s salty water, while a freshwater turtle’s health will be severely impacted and most likely lead to death.

Interesting Further Reading:

Final Takeaways

Turtles are reptiles as they’re cold-blooded, have claws, scales, lay shelled eggs, and have lungs to breathe air. They also don’t need to stay in and around water as much as amphibians do to live a healthy life.

More evidence that supports turtles being reptiles and not amphibians is the fact that they don’t go through a metamorphosis phase. Instead, they start off as small versions of their parents, just like mammals.

Sea turtles are no different in terms of the class of animal they fall into. They’re also reptiles that have adapted well to live a healthy life within the depths of the ocean.

Reptiles are more closely related to mammals as they have more features in common compared to amphibians. For example, reptiles and mammals are both born with lungs and need to breathe air for oxygen. Reptiles also usually have claws, just like most mammals do.