Alligator or Crocodile

This question is almost as old as these living pieces of history. Do you know how to tell the difference between these aquatic titans?


Since most who are reading this do not know me personally, you may be shocked to know that birds were not my first interest in the animal kingdom. In fact, on my wildlife "bucket-list" there is not a bird in the top THREE! So if birds were not my first professional interest, which animals were? Crocodilians.


My first two years out of college were spent working with American alligators and several species of crocodiles at a 'sanctuary' in the southern United States. While I have fond memories, learned much about myself, and gained many skills, the crocodilian world is not one I would enter again without a very different view. Why? Imagine if there existed a documentary called "Gator King" on Netflix, and that documentary followed some characters in this crocodilian world. It may reflect a similarly named documentary made popular by a blonde mulleted Oklahoman. Hey Netflix, do you want to see a world scarier than the big cat world?


The photo below reflects the time spent at this 'sanctuary.' It also reflects the values of much of the crocodilian world. Sensationalism over conservation. Money, fame, and power are often placed above the animal. While that is me in the photo, I strive to be a different person than the one in ankle-deep mud surrounded by alligators.


Zach with an alligator

I tell this story only to add my personal touch to this post. I have a deep appreciation for these toothy beasts, and I take great joy in writing any scaly-minded post!


Now, on to the learning!




Crocodilians of the World


First, let's define what a crocodilian is. 'Crocodilian' is the term used to describe the Order of these large reptiles. Orders are part of the organization system used by scientists to sort and classify species of organisms based on similarities. This is important for you, the reader, so that you know crocodilian does not just mean crocodile. It refers to crocodiles, alligators, caimans, and gharials.


Okay, enough taxonomy talk.


There are 24 species of crocodilians in the world currently recognized by scientists. There is existing research to indicate that there may be more species in some parts of Africa, however, more study is needed. The currently recognized species are:


Alligators & Caimans

  • American alligator - Alligator mississippiensis

  • Chinese alligator - Alligator sinensis

  • Spectacled caiman - Caiman crocodilus

  • Broad-snouted Caiman - Caiman latirostris

  • Yacare Caiman - Caiman yacare

  • Black Caiman - Melanosuchus niger

  • Cuvier's Dwarf Caiman - Palaeosuchus palpebrosus

  • Schneider's Smooth-fronted Caiman - Palaeosuchus trigonatus


Crocodiles

  • American Crocodile - Crocodylus acutus

  • African Slender-snouted Crocodile - Mecistops cataphractus

  • Orinoco Crocodile - Crocodylus intermedius

  • Australian Freshwater Crocodile - Crocodylus johnstoni

  • Philippine Crocodile - Crocodylus mindorensis

  • Morelet's Crocodile - Crocodylus moreletii

  • Nile Crocodile - Crocodylus niloticus

  • West African Crocodile - Crocodylus suchus

  • New Guinea Freshwater Crocodile - Crocodylus novaeguineae

  • Mugger Crocodile - Crocodylus palustris

  • Saltwater Crocodile - Crocodylus porosus

  • Cuban Crocodile - Crocodylus rhombifer

  • Siamese Crocodile - Crocodylus siamensis

  • Dwarf Crocodile - Osteolaemus tetraspis

  • False Gharial - Tomistoma schlegelii


Gharials

  • Indian Gharial - Gavialis gangeticus


While that list may be a little interest to you, there is some little kid with dreams of crocodilians that will pour over that list.



How to Tell an Alligator from a Crocodile


There exists in this world, a #dadjoke that I could use in this post. However, I will resist the temptation. Wait, no. I cannot resist.


You: "Hey Zach, what is the difference between an alligator and a crocodile?"


Zach: "The spelling."


Go ahead, hit the button. I will wait.



Okay, bad jokes aside, there are several key differences between alligators and crocodiles, but we will focus on three critical pieces of identification for these animals. They are simple, and they are easy to remember.



Alligator vs Crocodile Head Shape


The heads of alligators and crocodiles are uniquely shaped (usually). Alligators have a wide, rounded snout, whereas crocodiles have a tapered, pointed snout. Caimán, which is translated from Spanish as alligator, also have the rounded snout appearance. This rounded snout often gives alligators a bulkier or more robust head appearance.



There are some exceptions to this rule, as the dwarf crocodiles have somewhat rounded heads. However, there are no alligators or caimáns in Africa, so that should not create a problem for most readers.

Alligator head shape vs crocodile head shape

The graphic above is helpful, but the image below provides a profile angle where this shape is still quite obvious.


Nile crocodile head shape vs American alligator head shape


Alligator vs Crocodile Teeth


I am no artist, but I did my best to create a graphic showing how the teeth of alligators and crocodiles display when their mouths are closed. Ignore the colors, as I only added color to make the graphic appealing. Focus on the mouth. When an alligator or caimán's mouth is closed, only the teeth in the upper jaw are exposed. Like an overbite. However, when a crocodile has its mouth closed, teeth from the upper AND lower jaw are exposed, creating an interlock of teeth.

Tooth position of alligator vs tooth position of crocodile

Again, use the image below to see an actual example of this tooth positioning from alligators and crocodiles.


Alligator teeth vs crocodile teeth


American Alligator vs American Crocodile Range


Finally, there are few places in the world where you would expect to see an alligator and a crocodile sharing the same habitat. The exception? South Florida. The range fo the American alligator and the American Crocodile overlap in the southern extent of the alligator range and the northern extent of the crocodile range.


If you are wondering about alligators in the rest of the world, there is only one other species of 'alligator,' the Chinese alligator. It is functionally extinct from the wild. There are two to three species caimán that share range overlap with the American crocodile, Cuban crocodile, and the Morelet's crocodile, but these are not places most readers likely visit. However, if you do spend time in southern Cuba, the Yucatán peninsula, or Central America, apply the other two techniques for proper identification of caimán vs crocodile.

American alligator range vs American crocodile Range



What NOT to Use in Alligator and Crocodile Identification


There is a lot of misinformation about how to tell alligators and crocodiles apart. Here are some pieces of information that are not helpful:

  • Size

  • Color

  • Aggression

  • Smell

  • Taste (wait, what?)

People will frequently reference how much more aggressive crocodiles are than alligators. I refute that information. I have known crocodiles that were so docile, you might even argue they were cuddly. In fact, the west African crocodile is known to be docile enough that you can swim with them without fear of attack. However, I do not recommend that ANYONE ever tries that. Aggression is dependent on too many factors that are not related to species. A well-fed crocodile that is basking vs a female alligator at her nest will be very different in their levels of aggression. Stick to the tried and true methods from above.


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