Are Alligators Considered Reptiles? (And Why)

Alligators are reptiles. In its scientific classification, the alligator belongs to the class reptilia. Its order is Crocodilia, which is the same as the crocodile. However, the alligator belongs to the clade Globionta, and the crocodile is from Eusuchia.

There are many reptiles in the animal kingdom, including turtles, snakes and lizards. However, one must not mistake reptiles as amphibians, as they have differences in their biology.

Reptilian Features of Alligators

Alligators belong firmly in the reptile class of animals. Their bony scales, cold-blooded bodies, air-breathing and egg-laying abilities confirm their status as reptiles.

Let’s look at some of the features of reptiles and see how they apply to alligators…

1. Alligators Have Air-Breathing Lungs

Reptiles are air-breathing animals. They breathe through their lungs. This is different from fish (which have gills) and amphibians, some of which have gills when they are born.

All reptiles, including alligators need air to breathe, so they can’t survive underwater.

2. Alligators are Vertebrates

All reptiles, including alligators, are vertebrates. That is why they belong to the phylum called Chordata.

Lizards, turtles, crocodiles, and even snakes are all four-limbed vertebrates, although snakes limbs are vestigial.

3. Alligators have Scales

All reptiles have scales. This sets them apart from birds (which have feathers), mammals (which have fur), and amphibians (which have smooth skin).

Alligator scales are dry and tough, like armor to protect them from predators. 

Related Article: How Long Can Alligators Hold Their Breath?

4. Alligators are Cold-Blooded

Reptiles are cold-blooded, which means they need an external heat source to regulate their body temperature.

Alligators are well-known for basking in the warm sun to heat themselves. Unlike mammals, alligators can not heat themselves internally by consuming food, which means they can not live in cold climates.

Read More: How Far North do Alligators Live?

5. Alligators Lay Eggs

Although there are a small number of reptiles that give birth to live young, egg-laying is a key feature of reptiles.

All alligators lay hard-shelled eggs on land, which distinguishes them from mammals, marsupials, fish, and amphibians which give birth to live young or lay soft, jelly-like eggs in water.

Why is an Alligator not a Mammal?

Alligators are considered reptiles and not mammals, because they lay eggs instead of giving birth to live young, they have scales instead of fur, they are cold-blooded, and they don’t produce milk.

A mammal is also a vertebrate, but it produces milk. In addition, it has a mammary gland it uses to feed its offspring. Mammals also have hair on their bodies, and this hair or fur helps the mammals survive cold weather. 

Unlike the alligator, mammals are warm-blooded. They regulate their body temperatures and have no reliance on an internal heat source to achieve homeostasis.

Taxonomic Classifications of Alligators

Related Article: How Fast Can an Alligator Run on Land?

Below is the complete scientific family tree of the alligator. 

• Kingdom – Animalia
• Phylum – Chordata
• Class – Reptilia
• Order – Crocodilia
• Family – Alligatoridae

After the gator family, there are two sub-families called Alligatorinae and Caimaninae. The Alligatorinae is where the alligators belong. The caimans are part of the Caimaninae. 

There are many genus types under the sub-family of the Alligatorinae, but only the current alligator is extant. This means is that all its descendants in the evolutionary tree are already extinct. 

Here are some genera of the sub-family Alligatorinae:

• Allognathosuchus – grew up to 1.5 meters in length. It had strong jaws that crushed mollusks. 
• Arambourgia – an extinct genus named in 1950; it had non-serrated teeth and a deep snout. 
• Ceratosuchus – a swamp-dwelling predator that had triangular plates at the back of its head.
• Chrysochampsa – its fossil was found in the Golden Valley in North Dakota. It was first assigned in 1988. 

Did Alligators Evolve from Reptiles?

Alligators evolved from an ancient extinct reptile called the Brachychampsa. The fossil was found in Montana’s Hell Creek Formation. This earliest version of the alligator had short teeth and a large mouth, which indicates that it could eat turtles. 

The first alligator evolved sometime 245 million years ago. However, it was not until 80 million years ago that the first true crocodilians appeared. These crocodilians are now what scientists call alligatoroids, and the Brachychampsa was one of them.

Read More: Are Alligators Dinosaurs?

Are All Alligators Reptiles?

There are 8 recognised species of Alligators and Caimans extant today, and all of them are considered reptiles.

All crocodilians (including Alligators, Crocodiles, and Caimans) belong to the Reptilia class of animals, in the order Crocodilia.

Summary: Are Alligators Reptiles?

Alligators are reptiles, not amphibians. They are not the same as crocodiles, but they are related. The alligator came from an ancient species called Brachyhampsa, and the modern alligators of today first appeared 80 million years ago.

The alligator is endemic to the US and China only. The Chinese alligator is endangered, but the American alligator is not. There are Chinese alligators in the US because wildlife conservationists are protecting them.