Reptile Jargon and How to Decode It

Are you new to the reptile hobby? Did you come across a word, term, or acronym in your research that confused you? Do you have a reptile-loving friend who seems to be speaking in a different language?

Welcome to the world’s first online dictionary of reptile vocabulary! 

Or as I like to call it, Herper Gibberish. Yes, I have given our strange language a name.

This is a list of ~92 essential words, terms, and abbreviations that every budding reptile keeper should know. I’ve divided it into 3 sections, each organized alphabetically for your convenience. (I recommend using Ctrl+F if you’re looking for something specific.)

  • Acronyms — Pretty self explanatory. These are acronyms frequently seen in reptile forums, Facebook groups, etc.
  • Reptile Gibberish — General vocabulary used by experienced reptile keepers, and frequently used here at ReptiFiles.
  • Breeder Terminology — A selection of specific vocabulary used by breeders on their sites, classifieds ads, etc.

As for you experts out there: Can you find something here that you didn’t know before? ?


If you thought decoding Instant Messenger during the early 2000s was hard, check out a reptile forum sometime.  It’s only a matter of time before we start communicating entirely in emojis and acronyms.


(Alive on Arrival) This is the guarantee you want to see on a reptile or prey breeder’s website. It protects your money in case the shipping service mistreats the animal, and means that the breeder puts effort into how they package their animals


(African Soft Fur) The African soft fur is a type of rat that shares its habitat with ball/royal pythons, making them the pythons’ natural prey. They’re also irresistible to rodent-eating snakes. Snake not eating? An ASF can fix that.


(Amazon Tree Boa, aka Corallus hortulanus) Advanced level snake native to South America. Coloration is orange- or red-based rather than the green base seen in ETBs and GTPs.


Refers to 4 subspecies of the South American boa constrictor:

  • Boa constrictor constrictor
  • Boa constrictor imperator
  • Boa constrictor longicauda
  • Boa constrictor occidentalis


(Board of Inquiry) Forum on Fauna Classifieds where reptile keepers can go to research and inquire after the reputations of various breeders and reptile suppliers.


(Ball python, aka Python regius) Beginner-Intermediate level snake native to Africa. Extremely common in the reptile hobby. Available in hundreds of morph varieties.


(Crested Gecko Diet) Staple diet formula designed to provide a balanced source of nutrition for a crested geckos and several other gecko species. Often available in powder format, although some come as pellets. Not all CGDs are trustworthy.


(Ceramic Heat Emitter) A lamplike heat source that emits heat without light.


(Dead on Arrival) This is a complaint you might see on the BOI about certain reptile or prey breeders. It is also a consequence of shipping in inappropriate weather conditions.


(Emerald Tree Boa) Advanced level snake native to South America, named for its brilliant green color. ETBs and GTPs look a lot alike, but there are actually several differences. For example, ETBs give live birth and have rectangular snouts.


(Fauna Classifieds) Long-standing reptile forum where keepers come to post animals for sale, chat about the hobby, and leave reviews for breeders via the BOI.






(Green Tree Python, aka Morelia viridis) Intermediate-level snake native to southeastern Asia and part of Australia. Commonly confused with the emerald tree boa, but GTPs lay eggs and have a more rounded snout.


(Inclusion Body Disease) Contagious disease which affects pythons and boas. Caused by a virus similar to HIV in humans. Immediately fatal in pythons, eventually fatal for boas.


(Metabolic Bone Disease) One of the most common and easily preventable conditions in reptiles. Occurs when a reptile doesn’t get enough calcium, vitamin D3, or UVB. Bones become soft and even rubbery in severe cases. Fatal if not treated.


(Mercury Vapor Bulb) Floodlight-like bulb which produces both heat and UVB radiation for reptiles. Provides intense levels of UVB directly under the beam, but not so much to the surrounding area.


(Radiant Heat Panel) Reptile heating device which can be mounted to the wall or floor of a reptile enclosure. Warms the air of the enclosure by producing ambient heat rather than belly heat.


(Respiratory Infection, aka Upper Respiratory Infection) This is the reptile version of the common cold. Most often caused by incorrect humidity or low temperatures. Can be treated with antibiotics, fatal if not treated.


(Really Useful Bin) Used to describe plastic bins or tubs converted for use as a reptile enclosure. This acronym is more common outside of the United States, due to it being the name of a UK storage box manufacturer.


(Under-Tank Heater) Also known as a heat mat or heat pad. Used to heat the floor of a reptile enclosure, providing “belly heat.” Must be controlled with a thermostat for safe use.


Type of ultraviolet radiation produced naturally by the sun. Reptiles can see colors produced by this wavelength of light, but humans can’t. Seems to provide mental health benefits for diurnal reptiles as well as stimulate appetite.


Type of ultraviolet radiation produced naturally by the sun. Triggers a physiological process which helps both humans and reptiles make their own vitamin D3, which in turn helps them metabolize calcium. Lack of UVB can lead to MBD in many diurnal reptiles.

Reptile Gibberish

This is some of the most common jargon that gets tossed around the reptile community. And if it looks like a different language, it’s probably Latin. Don’t worry — just Google it for the common name. Or if you’re feeling brave, you can ask the poster for clarification.


System of counting male, female, and unsexed individuals of the same species. The first number is for males, the second for females, and the third for reptiles whose sex is not yet known. For example, if I had 6 bearded dragons: three male, two female, and one unsexed, then I would write that down as 3.2.1 bearded dragons.


The act of attributing human characteristics to a reptile. For example, buying an additional reptile to prevent another from getting “lonely.” Anthropomorphism is commonly criticized for getting in the way of correct reptile husbandry.


Lives in trees, adept at climbing.


A type enclosure that contains a miniature ecosystem centered around the primary animal housed inside of it. The goal for a bioactive enclosure is to be virtually entirely self-sustaining, using naturally-occurring flora and fauna to meet the animal(s) needs with minimal outside interference.


The reptile version of hibernation. This is a period of time during which reptiles slow down in order to survive the cooler season. Brumation is typically marked by loss of appetite and sleeping almost constantly, or at least reduced activity.


An animal that eats only meat — as in dead animals. May or may not include insects. Requires a high-protein diet.


Also known as “cohabbing,” this is the practice of keeping more than one reptile in the same enclosure. Not recommended for most reptile species, although this is considered a more acceptable practice outside of the United States.


Animal that does not produce its own body heat, relying on the temperature of its environment instead to regulate its metabolism.


Most active during the late evening and early morning hours.


Most active during the day.


Coating feeder insects with calcium and multivitamin powder to enhance their nutritional value and to correct nutrient ratios. “Shake and bake” method is most popular; insects are placed in a plastic or paper bag with supplement and shaken until evenly coated. Best paired with gutloading.


Refers to prey items that are purchased live and then killed (not stunned) immediately before feeding.


Refers to prey items, typically rodents, that have been euthanized, frozen, and then thawed to body heat (~100°F or 37-38°C). This simulates the heat signature of live prey without the risk of feeding live. Preferred by most reptile keepers for the convenience.


An animal which only eats fruit. This may include flowers, pollen, and nectar. Requires a high-carbohydrate diet.


A word breeders commonly use to describe a pregnant reptile.


Food given to prey rodents/insects/etc. to enhance their nutritional value. Verb form: “gutloading.”


Paired reproductive organ in male snakes and lizards. Usually a prominent landmark used for sexing.


An animal that only eats plants, including fruits and seeds. Typically requires a low-protein diet.


The practice of keeping reptiles/amphibians in captivity. Also used to describe the reptile community.


The activity of searching for reptiles in their natural habitat, typically for observation or photography. A herper is someone who goes herping regularly, although this term is also used in reference to reptile keepers.


General term referring to reptiles or amphibians. Abbreviation: “Herp(s).”


Blanket term referring to the overall care of a reptile. Includes diet, enclosure, temperatures, humidity, etc.


An animal which eats only insects. Requires a high-protein diet.

In shed

A reptile that is due to shed its skin soon. Will usually demonstrate duller coloration, defensiveness, and reduced appetite.

In the blue

Refers to the bluish/milky opaque color of a snake’s eyes when it first goes into shed. Snakes “in the blue” can’t see very well, but this stage of being in shed only lasts about 24 hours.


A genetic variation in a reptile’s color or pattern that is different from the Normal appearance. Similar to what is called a “breed” in dogs and cats, but morphs are less genetically distinct from each other compared to the distinction between breeds.


Most active at night.


An animal that eats both plant and animal matter. This includes meat, insects, fruits, and vegetables. Typically requires a medium-protein diet.


When a female animal reproduces without having her eggs fertilized. Offspring are essentially clones of the mother. Most notably observed in mourning geckos, but can occur in other reptile species as well.


Produces poison, usually as a self-defense adaptation.


System of reptile housing favored by breeders and large-scale collectors. Features a shelving-type unit with reptile enclosures stacked on top of one another via self-securing individual shelves.


The process of determining whether a reptile is male or female. Past tense: “sexed.”

Sexual dimorphism

Consistent differences in size and/or appearance between males and females of the same species.


Taxonomic category that is more specific than species. Usually used to distinguish genetically distinct localities of the same species from one another.


Flooring material used in a reptile enclosure. For example: paper towels, sand, or cypress mulch.

Temperature gradient

Range in temperatures from hot to cool in a reptile enclosure in order to accommodate thermoregulation. Also referred to as “temp gradient” or “heat gradient.”

Temp gun

Short for “temperature gun,” also known as a laser or infrared thermometer. Uses a laser to accurately measure the temperature of whatever it is pointed at. Very useful for determining temperature gradient in one’s husbandry.


Type of reptile enclosure that opens at the front and features opaque sides to help the reptile inside feel more secure.


Lives on the ground, not inclined to climb.


How reptiles manage their body temperature. Because they are cold-blooded, they will move from hot to cold areas (or vice versa) in their habitat based on what’s comfortable.


A device that regulates the heat output of an electrical heating device to a desired temperature. Most commonly used to make sure UTHs don’t overheat and cause burns.


Capable of injecting venom by biting. Venom is typically used for hunting prey.


Enclosure designed to at least partially simulate an animal’s natural habitat. Usually includes live plants and naturally-derived decor. May or may not be bioactive.

Breeder Terminology

Looking to buy a reptile? After brushing up on your Reptile Gibberish, here’s a few more key terms, abbreviations, and acronyms. These will help you decode reptile listings and impress breeders with your obvious proficiency.

100% het

Reptile has been confirmed to carry a recessive gene for a certain trait, usually through breeding.


Lacks pigment, usually melanin, most consistently resulting in red eyes. Albino does not necessarily mean pure white. Synonymous with amelanistic.


Lacks the pigment melanin, which is responsible for black, brown, and yellow coloration. Result is usually red or pink. Abbreviation: “amel.”


Lacks red pigment. Result is usually grayscale coloration, sometimes brown or yellow. Abbreviation: “anery.”


Lacking yellow or orange pigment. Sometimes used to describe an anerythristic animal, but not correct.


Means Captive Born or Captive Bred — usually the latter, but it’s wise to check. Captive born animals are not necessarily captive bred.


(Captive Born and Bred) Animal’s parents were bred in captivity and it was born in captivity.


(Captive Hatched) Animal was hatched in captivity, but parents were most likely wild.


Abbreviated: “Co-dom.” Heterozygous reptile demonstrates at least two dominant traits, all of which manifest in the phenotype.


Abbreviated: “Dom.” Genetic trait that will always be seen in the animals’ phenotype, whether heterozygous or homozygous.


First/Second/Third Filial Generation. F1s are the first offspring of a genetic project, F2s are the offspring of two F1s, F3s are the offspring of two F2s, and so on. Often used to describe CBB individuals.


An animal’s genetic makeup. These are the traits (seen or unseen) that get passed on to the next generation.


Animal carries different genes for the same trait.


Animal carries the same genes for the same trait.


Pure white animal. Not to be confused with albino.


(Long Term Captive) Animal was initially WC, but has been in captivity for a while. Generally means that the animal has been captive for at least a year, but not always, so it’s wise to check.


Abnormally dark animal due to increased melanin pigment. Often used to describe black morphs.


“Base model” reptile with the same patterning and coloration as found in the wild.


An animal’s appearance, as influenced by genotype. Phenotype helps breeders predict genotype.

Poss het

Short for possible heterozygous. An animal will be labeled “poss het” if the breeder has predicted genotype, but not proven the trait’s existence through breeding.


This is a “hidden” gene. An animal must be homozygous for a recessive gene to have it expressed in the phenotype. Sometimes abbreviated as “recc.”


(Wild Caught) Animal was captured from its natural habitat for sale in the pet trade.


More breeding terminology can be found in Living Art Reptiles’ list of reptile genetics vocabulary.


That…was a lot longer of a list than I thought this was going to be. But HEY, this is a dang comprehensive list of reptile vocabulary, if I do say so myself. Eventually I’m going to convert this into a permanent reference page.

Meanwhile, I’ll be recovering elsewhere.


But seriously, did I miss anything?

Let me know in the comments so I can update!

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  1. My best guess is “mainland”, but can you give me more context? The acronym/abbreviation is likely to be species-specific.

  2. What does ML mean it was after the scientific name. Is it gender.. is it male.. is it a boy?

  3. “Hypo” is short for “hypomelanistic,” which indicates that the animal produces less melanin (dark pigment) than normal. This typically results in animals that are paler than the wild type, but should not be confused with “amelanistic” / “amel”, which indicates that there is no melanin at all.

  4. I keep seeing Hypo in the breeder description but I have no idea what it means

  5. I confess I’m not sure! This is the first I’ve ever heard of that terminology.

  6. what does “z” mean?
    for example: Chinese Water Dragon-z

  7. Pre-established is generally used to refer to very young reptiles that hatched/were born recently, but they are taking meals regularly and growing well. A young reptile that isn’t established may not be eating regularly yet (as may be the case with snakes in particular).

  8. Newbie so maybe this is a dumb question but what does pre-established mean in maturity selection section on some sites?

  9. The only time I’ve come across VPI in the context of reptiles is referring to the snake breeder “Vida Preciosa International”, but VPI may be used to describe an axanthic morph ball python or a certain lineage of boas produced by that breeder.