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Here’s Why “Reptiles” Are Called Reptiles

Everyone knows what a reptile is, right? It’s a cold-blooded, scaly animal that usually lays eggs and may or may not have legs. Snakes, lizards, alligators, crocodiles, tortoises, and turtles are all reptiles. However, modern scientists have complicated things considerably, and you may be surprised to learn that officially there is no longer any such a thing as a reptile!

Reptiles are called “reptiles” because people needed a word to describe the creeping, crawling things in their environment. The word comes from ancient roots that mean ‘to creep’ or ‘slink’. Later on, scientists started to classify organisms, and the word passed down into taxonomical lexicon.

Taxonomy, the science of classification, is most often applied to sort living organisms into different groupings.

Scientists became a lot pickier about naming things because common nouns in widespread usage are imprecise and can refer to several different and unrelated things.  

Why Are Reptiles Called Reptiles?

The word “reptile” gets bandied about by conspiracy theorists, biologists, zoologists, herpetologists, and conservationists alike.

From the seventeenth century onwards, if you called someone a reptile, you were basically calling them a “creep” in modern terms.  The term was used as an adjective to denote “creeping or crawling”. 

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In the late fourteenth century, the word was used to describe any creeping or crawling animal and so embraced many more organisms than we associate with the word “reptile” today.

Reptiles have been called “reptiles” for etymological and taxonomical reasons. (Etymology studies the origin of words). The English language existed long before scientists started their scrutiny of all living things.

When scientists came along, they began refining the meanings of certain words due to their discoveries, and the need to describe them to the scientific community precisely.

Ordinary people used words for things they commonly encountered in their environments that came from the ancient historical roots of the language, which go back thousands of years.

In the thirteenth century, English speakers included various snakes, lizards, amphibians, worms, and fantastical monsters in the reptile category. The words “amphibian” and “reptile” were often used interchangeably.

In his Elements of Natural Philosophy published in 1689, John Locke noted that all terrestrial animals can be divided into quadrupeds or beasts, reptiles, “which have many feet”, and serpents “which have no feet at all”.

As you can see, the notion of what a reptile is has changed considerably since then, with snakes and legless lizards now being classified as reptiles. In Locke’s day, reptiles “who have many feet” would have included insects, scorpions, and spiders.

In Old English, the word “slincend,” which is related to our modern word, “slink,” was used for reptiles. So the original underlying idea is that reptiles were creeping, slithery animals that crawled on the ground.

However, living languages are constantly evolving, and the meanings of words change with the acquisition of knowledge and new words being created to describe new concepts. 

We have all heard the old linguistic cliché that there is no word for snow in the Eskimo languages of the Yupik and Inuit people. This sounds bizarre for humans who live in icy, snowy landscapes until you are told that they have several different words for snow, depending on its qualities. They have different words for falling snow, fallen snow, snow on the ground, snow crystals, etc.

Well, scientists are now doing the same things to our words for fish and reptiles!

After a lifetime of study, the famous evolutionary biologist and paleontologist Stephen Jay Gould concluded that there was no such thing as an animal called a fish!

Instead, he stated that there were five distinct classes of aquatic vertebrates, none of which is closely related to the other. It seems as though the word “reptile” is heading in the same direction, at least from a scientific perspective.

The Origins Of The Word “Reptile”

The word “reptile” was initially applied to all animals that crawl on their bellies

The word “reptile” is not strictly speaking a technical, scientific term. Here’s a bit of word history to explain. The word “reptile” came to modern English through the old Middle English word “reptil”.

The Middle English word came from Old French, which in turn came from the Latin word “repere,” meaning “to creep”. According to Merriam-Webster, the word was first recorded in the fourteenth century. 

The Latin word came from an even older group of languages called Proto-Indo-European, which had a root word “rep”, meaning “to creep or slink”. Our word “serpent” is closely related to the word “repere” and the Latin word “serpere”, which also means to “creep or crawl”. 

The word “reptile” was initially applied to all animals that crawl on their bellies, such as snakes, short-legged lizards, snails, and other creeping things. 

The Greek word “herpetón” clearly comes from the same ancient roots as the Latin word “repere” and means “creeping animal”. From this word, we derive the scientific term for the study of reptiles, which is “herpetology”.

However, modern scientists have gotten more technical than the simple Greek and now call “herpetology,” the “study of ectothermic tetrapods”.

The word “ectothermic” means cold-blooded, and the word “tetrapod” somewhat ironically means a four-footed animal. In science, the term “tetrapod” refers to all land-living vertebrates, including reptiles, mammals, and amphibians. Scientists say that even legless reptiles have, or once had, vestigial limbs and are descended from ancestors who had four limbs. 

The Greek word “herpetón” is the reason why hobbyists who keep reptiles and amphibians call themselves “herpers” or “herpetoculturists”. The famous Swedish taxonomist, botanist, and zoologist Carl Linnaeus, who first formalized a system for naming organisms, used the word “herptile” to refer to amphibians and reptiles.

Although the classification system of Linnaeus has undergone extensive revision since the seventeen hundreds when he was alive, the Cambridge dictionary still defines a “herptile” as a “reptile or amphibian”. 

In the eighteenth century, the word “reptile” was also used to refer to amphibians such as frogs, newts, and salamanders.

It was popularly used to describe a creature that creeps on many feet. For instance, Samuel Johnson, who wrote one of the most influential dictionaries in the history of English, called A Dictionary of the English Language, in 1755, describes the scorpion as a reptile. In his poem “The Task,” William Cowper, in 1785, called the snail a reptile.

So from an etymological point of view, the word “reptile” was used by the general public to generally describe several slithering, creeping, slinking organisms before the science of taxonomy got off the ground.

Since then, words have become a bit more specific, and insects, arachnids, and snails are no longer referred to as reptiles, even by the general public.

Reptiles And The Science Of Taxonomy

Carl Linnaeus kicked off the science of taxonomy with the publication of his Systema Naturae in 1758, and biologists have been arguing ever since.

It involves grouping organisms together into domain, kingdom, phylum, class, order, family, genus, and species. Modern taxonomical systems are designed to reflect evolutionary relationships between living and extinct organisms.  

Taxonomy organizes all living organisms into taxa. Its value is that it puts an organism in context so that scientists can better explain and grapple with concepts such as biodiversity, ecosystems, environmental and animal conservation.

Modern scientists use genetic, behavioral, morphological, anatomical, and biochemical information to describe and arrange animals into categories. 

These categories allow a better understanding of the type of organism being studied and standardizes scientific language so that everyone knows precisely what you are talking about in your erudite scientific paper.

Common names for animals that you and I would use every day can be applied to a variety of different ones that bear no objective relation to each other. They therefore lack precision. 

Cladistics is a taxonomical system that originated with the German entomologist Willi Hennig in the twentieth century. It is a particular method for theorizing about the relationships between different organisms and comes with a set of built-in assumptions, limitations, and procedures.

Before cladistics came along, a French zoologist, Pierre Latreille, divided tetrapods into mammals, birds, amphibians, and reptiles, and this was and still is widely accepted by most people.

The word “reptile” is still used by the general public and scientists alike,  but now, scientists no longer use it to identify reptiles as an evolutionary group thanks to cladistics.

So you can still visit a Reptile Park and expect to see snakes, lizards, tortoises, and alligators, and the word “reptile” probably isn’t going anywhere anytime soon.

Cladistics has been accepted as the best method for phylogenetic analysis because it allows scientists to test the hypothetical relationships between animals. Shared characteristics, the basis of the Linnaean system, is not sufficient to establish a scientifically verifiable relationship between various organisms. The cladistic system uses the presence of shared derived characteristics based on their ancestry.

The word ‘reptile’ may have an obvious meaning in every day language, but its definition is hotly debated among the scientific community

However, with its strict rationality, cladistics has put the cat among the pigeons with some of the traditional groupings of animals because it is a more rigorous taxonomic system. It divides organisms into clades. Mammals and birds fall into distinct clades because they branched off from a common ancestor at some point in evolutionary history.  

The problem with the category Reptilia is that scientists don’t recognize it as a true clade because many extinct reptiles are the ancestors of birds and mammals as well as modern reptiles. There is no recognizable point in history where the Reptilia branched off from a particular ancestor.

Taxonomy And The Class Reptilia

Reptiles are tetrapods that belong to the scientific class Reptilia. Today it includes, snakes, crocodiles, alligators, amphibians, lizards, turtles, the tuatara, and many extinct dinosaurs. Yes, dinosaurs such as sauropods, theropods, plesiosaurs, pterosaurs, and mosasaurs are reptiles.

Check out my article here giving you all the facts about what exactly dinosaurs are actually classed as.

Surprisingly, some modern scientists are inclined to include birds in this class because they have discovered that crocodiles are more closely related to birds than to lizards!

The Reptilia class or clade consists of four orders:

  1. Crocodilia – which includes alligators, caimans, gharials, and crocodiles.
  2. Testudines – which includes tortoises, sea turtles, and turtles
  3. Squamata – which includes snakes, geckos, and lizards.
  4. Sphenodontida – which includes tuataras

Modern biologists use two classification systems:

  1. The Linnaean system, developed by Carl Linnaeus, where organisms are classified according to their characteristics, regardless of who or what their ancestors were.
  2. The phylogenetic clade system designed by biologist Willi Heinig in the 1940s, where organisms are categorized according to their ancestry and not just their visible features. 

In the Linnaean system, a cold-blooded, egg-laying animal with scales and four legs was likely to be classified as a reptile based purely on its characteristics.

Amphibians such as frogs and toads were originally classed together with reptiles by Carl Linnaeus under the heading Amphibia.

Later the Linnaean system divided Amphibia into three divisions based on whether they crept, slithered, or swam, which meant some kinds of fish were even included initially. 

Linnaeus called the branch Amphibia, within which he distinguished between serpents and reptiles. Reptiles:

  • had feet
  • laid eggs
  • had flat, naked ears
  • consisted of lizards, turtles, crocodiles, frogs, and salamanders

While serpents:

  • didn’t have feet
  • laid eggs
  • had hemipenes
  • include snakes, caecilians, and legless lizards

However, scientists later discovered that it is not only snakes that have hemipenes but also lizards, geckos, and worm lizards. They also started looking at the ancestry of various animals called reptiles and discovered more genetically distinct characteristics and diversity.

Why is a bird a reptile? In the phylogenetic system, birds belong to the Diapsida group, which includes all of the other living reptiles. Therefore phylogenetically speaking, a bird is a reptile.

Birds are more closely related to reptiles, crocodiles in particular, than any other type of organism. In fact, birds are recognized as the only living dinosaurs left. Like crocodiles, they come from dinosaur ancestors called archosaurs.

What’s In A Name?

Constant battles are being waged in taxonomy despite the International Commission of Zoological Nomenclature (ICZN), which keeps the official records of all species names. In extreme cases, the term ‘taxonomic vandalism’ is used to describe the failure of scientists not to respect species names.

The correct nomenclature of different organisms can be critical on a practical level. In an article in the Smithsonian Magazine, this is illustrated by the case of the African spitting cobra, a venomous snake that can spit venom into your eyes or deliver it via a bite.

In the ICZN, the cobra belongs to the genus Spracklandus. However, this name is very seldom used by scientists and researchers who instead refer to it as Afronaja in their papers and articles.

If you are the unfortunate victim of venom by this snake and you tell the doctor treating you that a Spracklandus bit you, you may not be given the correct antivenom. This is according to a herpetologist and taxonomist at the Museum of Zoology at the University of Sao Paulo.

The name Spracklandus is the subject of a heated debate that could decide the future of an entire field of science. It was an Australian who gave the name Spracklandus to the cobra, and he has been accused of taxonomic vandalism by scientists who don’t recognize his credentials.

These vandals are people who like to name many new taxa without presenting sufficient scientific evidence for their classifications. Instead, they use the original scientific research of others to claim that they have discovered a new taxa.

Taxonomic vandals are described as glory seekers whose goal is self-aggrandizement. They want to be recorded in the history books as naming multiple new species without consideration for the ethical issues involved in taxonomy. The scientists who oppose them say they are bringing the whole field of taxonomy into disrepute. 

There is a legal vacuum that means that the ICZN has no legal recourse against self-publishers who generate nomenclature by using unethical or non-scientific methods. This gives rise to lousy science, according to taxonomists.


As a layperson, you can safely call a reptile a “reptile” comfortable in the knowledge that the listener will appreciate what you mean. You don’t need to explain that it is a cold-blooded, scaly little creeper.

However, there seems to be an increasing war of words in scientific fields, which means that you had better choose your terms carefully when it comes to taxonomy.