Reptile or Amphibian? An Identification Key

Through a series of steps, this key will help you to learn the basics of identifying the main families of reptiles and amphibians. The steps are simple, all you'll need to do is examine the animal and determine such features as the type of skin it has, whether or not it has a tail, and whether or not it has legs. With these bits of information, you'll be well on your way to identifying the type of animal you're observing.

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Getting Started

Reptile or Amphibian?
Courtesy of Laura Klappenbach

As you proceed, please keep in mind:

  • This key assumes that you are pretty certain the animal you're identifying is an amphibian or a reptile of some kind. For instance, this key doesn't apply to creatures that have feathers, fur, fins, or six legs and compound eyes—if you're observing any such animal, then you're not dealing with a reptile or an amphibian.
  • The identification of any animal is a cumulative process that relies on careful observation. These steps enable you to categorize amphibians and reptiles with increasing precision. This means the more questions you answer, the more detailed a classification you can obtain.
  • Links to previous steps enable you to revisit past questions and understand the decisions that preceded each step.
  • Once you have reached the end of an identification series, there is a summary of the animal's taxonomic classification.

Although this identification key does not enable the classification of animals down to the level of individual species, in many cases it enables you to identify an animal's order or family.

02
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Amphibian or Reptile?

Amphibian or Reptile?
Courtesy of Laura Klappenbach

How to Tell Amphibians and Reptiles Apart

An easy way to distinguish between an amphibian and a reptile is to examine the animal's skin. If the animal is an amphibian or a reptile, its skin will either be:

Hard and scaly, with scutes or bony plates - Image A
Soft, smooth, or warty, possibly moist skin - Image B

What next?

  • If the animal's skin is hard and scaly, with skutes or bony plates as in Image A, then the animal is a reptile. If this is the case for the animal you are observing then click here.
  • If on the other hand the animal's skin is soft, smooth, or warty and is possibly moist as in Image B, then the animal is an amphibian. If this is the case for the animal you are observing then click here.
03
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Reptile: Legs or No Legs?

Reptile: Legs or No Legs?
Courtesy of Laura Klappenbach

Narrowing the Reptile Field

Now that you've determined your animal is a reptile (due to its hard, scaly, skin with scutes or bony plates), you're ready to look at other characteristics of its anatomy to further classify the creature.

This step is actually pretty simple. All you need to look for is legs. Either the animal has them or it doesn't, that's all you have to determine:

Has legs - Image A
Does not have legs - Image B

What does this tell you?

  • Well, you know the animal is a reptile already, and if the animal you're looking at has legs as in Image A, it could be one of several types of reptile such as a lizard, turtle, crocodile, or tuatara.
  • On the other hand, if the animal you're looking at doesn't have legs as in Image B, then it is either some type of snake or amphisbaen.
04
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Amphibian: Legs or No Legs?

Amphibian: Legs or No Legs?
Inset photo © Venu Govindappa / Wikipedia.

Narrowing the Amphibian Field

Now that you've you've determined that your animal is a amphibian (due to its soft, smooth, or warty, possibly moist skin), it's time to look for legs.

Has legs - Image A
Does not have legs - Image B

What does this tell you?

  • You know the animal is a amphibian, so if it has legs as in Image A, it could be one of several types of amphibians such as a amphibian such as a frog, toad, salamander, or newt. If this is the case for the animal you are observing then click here.
  • On the other hand, if the amphibian you're looking at doesn't have legs as in Image B, then it is a caecilian.
05
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Amphibian: Tail or No Tail?

Amphibian: Tail or No Tail?
Courtesy of Laura Klappenbach

All the Difference Between Salamanders and Toads

Now that you've determined that your animal is an amphibian (due to its soft, smooth, or warty, possibly moist skin) and it has legs, you need to next look for a tail. There are only two possibilities:

Has a tail - Image A
Does not have a tail - Image B

What does this tell you?

  • If the animal has a tail as in Image A, then it's a salamander or newt.
  • If the animal does not have a tail as in Image B, then it's either a frog or a toad. If this is the case for the animal you are observing, then click here.
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Amphibian: Warts or No Warts?

Amphibian: Warts or No Warts?
Courtesy of Laura Klappenbach

Sorting the Toads From the Frogs

If you have determined that your animal is an amphibian (due to its soft, smooth, or warty, possibly moist skin) and it has legs, and it lacks a tail the you know you're dealing with a toad or a frog.

To distinguish between frogs and toads, you can look at their skin:

Smooth, moist skin, no warts - Image A
Rough, dry, warty skin - Image B

What does this tell you?

  • If the animal you're identifying has smooth, moist skin and no warts, it's a frog.
  • If, on the other hand, it has rough, dry, warty skin, you've got a toad.
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Klappenbach, Laura. "Reptile or Amphibian? An Identification Key." ThoughtCo, Apr. 5, 2023, thoughtco.com/reptile-or-amphibian-identification-key-130251. Klappenbach, Laura. (2023, April 5). Reptile or Amphibian? An Identification Key. Retrieved from https://www.thoughtco.com/reptile-or-amphibian-identification-key-130251 Klappenbach, Laura. "Reptile or Amphibian? An Identification Key." ThoughtCo. https://www.thoughtco.com/reptile-or-amphibian-identification-key-130251 (accessed March 29, 2024).