Difference between Crocodile and Alligator | 7 Scientific Facts

difference between crocodile and alligator

The most well-known water-dwelling lizards are crocodiles and alligators. As both of them generally appear similar to us, we often use their names interchangeably. But they are completely two different semi-aquatic reptiles with some bold factors that separate one from another. 

Crocodiles and alligators are from the same order; Crocodilia; existing on the planet for millions of years. Both these carnivorous creatures lay eggs and have thick armored skin that protects them against water loss for having boney scales. These scales are generally known as Scutes. 

Despite many similarities, there are some notable facts worth knowing in order to tell them apart. The difference between crocodile and alligator lies in several areas like their families, physical characteristics, habitats, behaviors, etc. 

While crocodiles are considered more aggressive reptiles with sharp teeth, alligators are comparatively tame. The most common visible characteristics that can tell a crocodile from an alligator are their different types of snouts, positioning of teeth, and body length. 

This article will focus on all the factors that can help you identify between a crocodile and an alligator correctly. No more confusion in the future, so let’s proceed.

Comparison chart

TaxonomyCrocodiles are from the Crocodylinae Subfamily, which belongs to the Crocodylidae Family and the Crocodyloidea Superfamily of Crocodilia Order.Alligators are from Alligatorinae Subfamily, belong to the Alligatoridae Family and Globidonta Clade of Crocodilia Order.
DistributionCrocodiles are extant in tropical regions worldwide.Alligators are extant in the southeast USA, Mexico, and eastern China.
ClimateCrocodiles are not extant in the temperate region.Alligators can be found in the temperate region.
HabitatA species of crocodile (Crocodilus porosus) lives in brackish water and seawater.Alligators can be found in brackish water but not in seawater.
HeadCrocodiles have narrower and longer heads than alligators.Alligators have broader and shorter heads than crocodiles.
SnoutCrocodiles have a more conical (V-shape) and narrow snout compared to the alligators.Alligators have a U-shaped wider snout.
TeethCrocodiles’ teeth of the upper and the lower jaw are visible when their mouths are closed.Alligators’ teeth of the upper jaw are visible when their mouths are closed.
FeetCrocodiles have more webbing on the toes of their hind feet than alligators.Alligators have less webbing on the toes of their hind feet than crocodiles.
Salt GlandCrocodiles have functioning salt glands.Alligators have non-functioning salt glands.
AggressionCrocodiles are more aggressive than alligators.Alligators are less aggressive than crocodiles.
SpeedCrocodiles’ run may reach up to 9 miles per hour when on the ground.Alligators’ run may reach up to 11 miles per hour when on the ground.


Crocodiles are large semi-aquatic reptiles from many tropics around the world. The word Crocodile derives from the ancient greek term Crocodilos, which means Lizard. Crocodilos consist of Croco and Dilos. Croco means Pebbles, and Dilos means Worm. So the word Crocodilos literally means Pebble worm.  Here are some characteristics of crocodiles described below. 

Crocodiles Fram


According to the ITIS (Integrated Taxonomic information system), the taxonomy of crocodile is 

kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Crocodilia
Family: Crocodylidae
Genera: Crocodylus, Osteolaemus, Mecistops

Crocodiles are from the Crocodylidae family. The subfamily of these semi-aquatic reptiles is Crocodylinae. There are 15 species found under the Crocodylidae family that can be referred to as true crocodiles

Crocodiles are from Crocodylus, Mecistops, and Osteolaemus extant genera from Euthecodon, Rimasuchus, Voay extinct genera of Crocodylinae Subfamily, which belongs to Crocodylidae Family. The extinct Mekosuchinae Subfamily belongs to the same Crocodylidae Family of crocodiles.

Crocodile species

Some existing species of Crocodiles are

  • American Crocodile (Acutus)
  • Cuban Crocodile (Rhombifer)
  • Saltwater crocodile (Porosus)
  • Nile crocodile (Niloticus)
  • African Dwarf Crocodile (O.tetraspis)  
  • African slender-snouted Crocodile (M.Cataphractus) 

There are nineteen extinct crocodile species as per fossil records. These species are: 

  • Australosuchus clarkae
  • Brochuchus parvidens
  • Brochuchus pigotti
  • Crocodylus anthropophagus
  • Crocodylus checchiai
  • Crocodylus palaeindicus
  • Crocodylus thorbjarnarsoni
  • “C.” gariepensis
  • “C.” megarhinus
  • Euthecodon arambourgii
  • Euthecodon brumpti
  • Kambara implexidens
  • Quinkana babarra
  • Quinkana fortirostrum
  • Quinkana meboldi
  • Quinkana timara
  • Rimasuchus lloydi
  • Trilophosuchus rackhami
  • Voay robustus

Physical characteristics

Some visible characteristics of a crocodile distinguish it from an alligator. The boldest physical characteristics of a crocodile are the length, shape of its snout, and teeth’ visibility. 

Snout: The jaw of a crocodile is one of the first visible factors that distinguish it from an alligator. The snout of a crocodile is V-Shaped, which is long and pointed. However, differences can be seen among various species. Crocodiles from some areas may have various types of jaws, such as the West African dwarf crocodile, which has a small and comparatively blunt snout. 

Teeth: Crocodiles are Polyphyodont animals. It can replace each of its eighty teeth up to fifty times during the lifespan. Because of the pointed and V-shaped snout, a couple of long and sharp teeth remain visible even after its mouth is closed.  

Size: The size of an adult crocodile is usually a couple of feet longer compared to an alligator. A full-grown alligator can be up to 19 feet long. The saltwater crocodile can be up to 18 feet long, the American crocodile can be up to 16 feet long, and the length of a Nile crocodile can be up to 14 feet.

Color: Generally, Crocodiles are light tan, grayish-green, olive, or brown in color.

Location and habitat

Most crocodiles can be found in the tropical areas of Southeast Asia, Africa, America, and Australia. 

Crocodiles have a salt-excreting gland located on the tongue, which makes them more favorable to stay in the salt waters. Crocodiles can also be seen on rivers, lakes, and wetlands. 


The behavioral difference between crocodile and alligator is a significant one. Crocodiles are more aggressive compared to alligators. Among all the species, the Saltwater and Nile crocodiles are considered the most aggressive. They are more likely to attack humans. However, not all species of crocodiles are equally aggressive; some are pretty much wary of humans.  


Crocodiles are athletic reptiles. A swimming crocodile can reach speeds up to 21 mph. And while they are on the ground, a crocodile can reach about 9 miles per hour.


Alligators are large semi-aquatic reptiles mostly found in freshwaters around the world. The word Alligator possibly derives from the Spanish term el Lagarto, which means the Lizard

Alligators Fram

Later the term el Lagarto came into English and was mostly spelled as alagarto or allagarta (Alligator as a modern term). Here are some characteristics of alligators described below. 

kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Crocodilia
Family: Alligatoridae
Genera: Alligator

We call semi-aquatic reptiles from Alligatorinae Subfamily alligators. Alligatorinae Subfamily belongs to Alligatoridae Family, Globidonta Clade, Crocodilia Order, Eusuchia Clade, Metasuchia Clade, Mesoeucrocodylia Clade, Crocodyliformes Clade, Reptilia Class, Chordata Phylum, Animalia Kingdom. 

Alligators have one extant and ten extinct genera (as per fossil records). The extant genus is Alligator. Some extinct genera are Allognathosuchus, Arambourgia, Ceratosuchus, Chrysochampsa, Hassiacosuchus, Krabisuchus, Navajosuchus, Procaimanoidea, Protoalligator, and Wannaganosuchus. 

Caimans are from the Caimaninae Subfamily, which belongs to the same Alligatoridae Family of alligators.

Alligator species

There are two extant and six extinct (as per fossil records) species from Alligator Genus. Extant alligator species are Alligator mississippiensis (American alligator) and Alligator sinensis (Chinese alligator). 

Extinct alligator species are Alligator hailensis, Alligator mcgrewi, Alligator mefferdi, Alligator olseni, Alligator prenasalis, and Alligator thomsoni.

Physical characteristics

The boldest difference between crocodiles and alligators lies in their physical characteristics. If you clearly understand an alligator’s visible characteristics, you will never get confused between these two similar reptiles ever. 

Snout: An alligator has a wide jaw compared to a crocodile. The snout of an alligator is generally U-Shaped and rounded. According to the scholars, an alligator’s snout shape is like this because of its food habit. A broader snout provides an alligator higher strength from the mouth that makes hunting easy.

Teeth: When an alligator closes its mouth, no bottom teeth can be visible from the outside. Because of U-Shaped wider snout, an alligator can hide all the teeth inside of its mouth. A full-grown alligator has eighty conical-shaped teeth. Like the crocodiles, an alligator can replace each of its teeth up to several times. It may go through around 3000 teeth in its lifetime. 

Size: When it comes to size, the alligators are usually a couple of feet shorter compared to crocodiles. The maximum length of an American alligator is 15 feet, the longest of all species. On the other hand, the Chinese species of alligators are pretty short. Generally, the length of a Chinese alligator is 5 feet and weighs 36-45 kg. 

Color: The alligators are darker blackish-grey. The American alligators can be black, olive, brown, or grey.  

Location and habitat

Alligators can be found only in some specific regions like the Southeastern US, Eastern China. The number of alligators in the US is much higher than the crocodiles. The current number of alligators in the US is more than 3 million.

Alligators are freshwater reptiles. They cannot be found in saltwater in general. Although, they can be found sometimes in slightly salty waters like in river estuaries. 


Alligators are ectothermic animals. They are cold-blooded and don’t have the capability to regulate their own body temperature.  Alligators are tame in nature when compared to crocodiles. Although that doesn’t mean they are not aggressive. Alligators are aggressive enough to hunt their prey and when defending themselves from any possible threat. 

However, the larger species of alligators are more aggressive in nature than the smaller ones. The smaller species of alligators have higher tolerance levels compared to any other species.


Alligators are athletic reptiles like crocodiles. A swimming alligator can reach up to 22 mph speed in the water and 11 miles per hour on the ground.

The key differences between Crocodile and Alligator

  1. Crocodiles are from the Crocodylinae Subfamily, which belongs to the Crocodylidae Family and the Crocodyloidea Superfamily of Crocodilia Order. Alligators are from Alligatorinae Subfamily, belong to the Alligatoridae Family and Globidonta Clade of Crocodilia Order.
  2. Crocodiles’ teeth of the upper and the lower jaw are visible when their mouths are closed. Alligators’ teeth of the upper jaw are visible when their mouths are closed.
  3. Crocodiles are extant in tropical regions worldwide. Alligators are extant in the southeast USA, Mexico, and eastern China.
  4. Crocodiles have narrower and longer heads than alligators.
  5. Crocodiles have V-shape snouts. On the other hand, alligators have U-shaped snouts.
  6. Crocodiles have functioning salt glands, whereas alligators have non-functioning salt glands.
  7. Crocodiles are more aggressive than alligators.

The commercial importance of crocodiles and alligators

Crocodiles and alligators have commercial importance for their meat, skin, oil, teeth, and claws. Farming of these reptiles is considered a lucrative business across the world. 

Alligator farming is mostly popular in the southeastern US regions. States like Louisiana and Florida have the largest alligator population in the world, with many large alligator ranches around. 

On the other hand, crocodile farming is very popular in Thailand. There are around 1000 crocodile farms across Thailand, with a population of 1.2 million crocodiles. 

Crocodile and alligator skin are pretty much expensive. They are used to produce shoes, handbags, wallets, belts, and other luxury products.

Frequently asked questions (FAQs):

Who would win alligator or crocodile?

Either can win. Just because crocodiles are more aggressive in nature and have sharper teeth than alligators, it is more likely to say that a crocodile would win in a fight against an alligator.

Which is bigger alligator or crocodile?

Crocodiles are usually a couple of feet longer compared to alligators.

Can a crocodile and alligator mate?

They belong to different families and genera. Just because both these reptiles look similar, that doesn’t mean they can mate or be intercrossed. No, crocodiles and alligators cannot mate

Do crocodiles eat humans?

Crocodiles are carnivorous animals. But, it is not like they are set out to hunt humans only. An opportunistic hunter like a crocodile can eat any animal if they are hungry enough or in a mood to hunt. Among all types, the saltwater crocodiles and the Nile crocodiles are the most ferocious ones. Always keep a safe distance from them.


Crocodiles and alligators are two large semi-aquatic reptiles that almost look the same. They belong to the same order: Crocodilia, both are carnivorous and share many other factors that make us confused to tell them apart. Having that in mind, this article has demonstrated the difference between crocodile and alligator through a thorough discussion on the fields they differ.

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