The KBN Reptiles Dictionary
Reptile Terms & Abbreviations Explained
Every hobby has its own language, and reptile keeping is no different. Our KBN Reptiles Dictionary explains the most common terms, abbreviations and scientific words you'll come across, explaining everything you need to know in simple, easy-to-understand language.
A
Abdomen
The abdomen is the rear section of an animal's body. In spiders, tarantulas and scorpions, it contains many of the animal's vital organs, including the digestive and reproductive systems. In spiders and tarantulas, the abdomen also contains the spinnerets, which produce silk.
Adult
An adult is an animal that has reached full physical development and sexual maturity. Adult reptiles and invertebrates have completed most of their growth, although some species may continue to increase in size slowly throughout their lives.
Alligator
An alligator is a large reptile closely related to crocodiles. They can be distinguished by their broader, U-shaped snout and the fact that, when their mouth is closed, the lower teeth are usually hidden. Alligators are mainly found in the United States and China.
Arboreal
A species that naturally spends most of its time living in trees.
Arthropod
An arthropod is an invertebrate belonging to the phylum Arthropoda. Arthropods have a hard exoskeleton, jointed legs and segmented bodies. This group includes spiders, scorpions, insects, millipedes, centipedes and crustaceans, making it the largest group of animals on Earth.
Ambient Temperature
The general air temperature within an enclosure. This is different from the basking temperature and should be measured on both the warm and cool sides of the enclosure.
Amphibian
A cold-blooded vertebrate belonging to the class Amphibia. Amphibians include frogs, toads, salamanders and newts. Unlike reptiles, most amphibians have smooth, moist skin and many spend part of their life in water.
Aquatic
Aquatic describes an animal that lives primarily in water. Aquatic species are specially adapted for swimming and obtaining food in rivers, lakes, ponds or oceans.
B
Basking
Basking is the behaviour of sitting under a heat source or in direct sunlight to raise body temperature. As reptiles are ectothermic (cold-blooded), basking is essential for digestion, movement, immune function and overall health. Captive reptiles should always be provided with an appropriate basking area that matches the needs of their species.
Basking Spot
The warmest area of an enclosure where a reptile can raise its body temperature by sitting under a heat source.
Bedding
A material used on the floor of an enclosure to provide comfort or absorb waste. In reptile keeping, the term substrate is generally preferred, as it more accurately describes the materials used to recreate a reptile's natural environment.
Bioactive
A naturalistic enclosure containing live plants and beneficial invertebrates such as springtails and isopods that help break down waste.
Book Lungs
Book lungs are the breathing organs found in spiders, tarantulas and many other arachnids. They consist of thin, folded membranes arranged like the pages of a book, allowing oxygen to enter the body and carbon dioxide to leave. Book lungs are located on the underside of the abdomen.
Brumation
A natural period of reduced activity during the colder months, similar to hibernation, experienced by many reptiles. During brumation, reptiles may eat less, sleep more and become less active.
Burrow
A burrow is a tunnel or chamber dug into the ground by an animal for shelter, protection or hunting. Many reptiles and invertebrates naturally live in burrows to escape predators, regulate their body temperature or maintain suitable humidity.
C
Caecilian
A caecilian is a limbless amphibian. Although they resemble snakes or worms, they are not reptiles. Most caecilians spend their lives burrowing underground or in water and are rarely seen in the wild.
Carapace
The carapace is the upper part of a turtle or tortoise's shell, covering and protecting its back. In arachnids, such as tarantulas and scorpions, the carapace is the hard plate covering the front section of the body (cephalothorax).
Carnivore
An animal whose diet consists primarily of other animals.
CB (Captive Bred)
Animals that have been bred in captivity rather than taken from the wild.
Cephalothorax
The cephalothorax is the front section of the body in arachnids and some other arthropods. It is formed by the head and thorax being fused together into a single body segment. In spiders and tarantulas, the cephalothorax contains the eyes, mouthparts, brain, legs and muscles used for movement.
The hard plate covering the top of the cephalothorax is known as the carapace.
CHE (Ceramic Heat Emitter)
A Ceramic Heat Emitter (CHE) is a heating device that produces heat without emitting light. They are commonly used to provide day or night-time warmth and should always be used with a suitable thermostat.
CF (Captive Farmed)
An animal that has been bred, hatched or raised on a commercial breeding farm, rather than being bred by a private breeder. The term is commonly used for reptiles produced in large-scale breeding facilities and should not be confused with Captive Bred (CB).
CH (Captive Hatched)
Eggs collected from the wild and hatched in captivity.
Chelicerae
Chelicerae are the mouthparts of arachnids. In spiders and tarantulas, they contain the fangs, which are used to inject venom into prey and begin the feeding process. Although often mistaken for jaws, the chelicerae are specialised appendages unique to arachnids.
Chelonia
Chelonia is the scientific order that includes all tortoises, turtles and terrapins. The term is often used by reptile keepers and veterinarians when referring to these animals collectively.
Clutch
A group of eggs laid by a reptile at the same time.
Cohabitation
Keeping more than one animal together in the same enclosure. While some species can live communally, many reptiles are solitary and should be housed alone to prevent stress, aggression or injury.
Crepuscular
An animal that is most active at dawn and dusk, rather than during the middle of the day or throughout the night.
Crocodile
A crocodile is a large, semi-aquatic reptile belonging to the order Crocodylia. They have long, narrow snouts, powerful jaws and are found in tropical regions throughout the world. Crocodiles are opportunistic predators, feeding on fish, birds and mammals.
D
Dechlorinator
A liquid treatment added to tap water to remove chlorine and chloramine, making it safe for reptiles, amphibians and aquatic animals.
Diurnal
A species that is mainly active during daylight hours and rests at night.
E
Ecdysis
The scientific name for the process of shedding old skin. See also Shedding.
Ectothermic
Animals that rely on external heat sources, such as the sun or a heat lamp, to regulate their body temperature. Reptiles are ectothermic, which is why providing the correct temperatures is so important.
Enclosure
The home or habitat in which an animal is kept. This may be a vivarium, terrarium, paludarium or aquarium depending on the species.
Exoskeleton
An exoskeleton is a hard outer skeleton that supports and protects the body of an invertebrate. Unlike the internal skeleton of vertebrates, an exoskeleton is on the outside of the body and must be shed as the animal grows. Arthropods such as spiders, scorpions, insects and crustaceans all have exoskeletons.
F
Fangs
Fangs are specialised teeth used by venomous animals to inject venom into their prey or as a defence. In snakes, fangs are modified teeth found in the upper jaw, while in spiders and tarantulas they are located on the chelicerae. Not all reptiles or arachnids have venomous fangs.
Faunarium
A small, portable plastic enclosure used for temporarily housing or transporting reptiles, amphibians, invertebrates or livefood. Faunariums are ideal for transport or short-term use but are generally not suitable as permanent homes for most animals.
Fossorial
A species adapted to spending much of its life underground, living in burrows or digging beneath the substrate.
Frugivore
An animal that eats mainly fruit as part of its diet.
G
Gecko
A gecko is a type of lizard belonging to the infraorder Gekkota. Most geckos have specialised toe pads that allow them to climb smooth surfaces such as glass and walls. They are found throughout tropical and subtropical regions, and many species are popular pets due to their fascinating behaviour and relatively straightforward care.
Gravid
A term used to describe a pregnant female or a female carrying developing eggs.
Gut-loading
The process of feeding nutritious foods to live insects before offering them to your reptile. This increases the nutritional value of the insects.
H
Hatchling
A hatchling is a young reptile, amphibian or invertebrate that has recently emerged from its egg. Hatchlings are fully independent from birth and must quickly begin feeding, growing and adapting to their environment. Their care requirements often differ from those of adults, particularly regarding enclosure size, diet and humidity.
Hemipenes
Hemipenes are the paired reproductive organs of male snakes and lizards. Unlike mammals, males have two hemipenes, although only one is usually used during mating. They are normally kept inside the base of the tail and are only everted (turned inside out) during breeding or, occasionally, due to injury or illness.
Hemipenal Bulge
The hemipenal bulge is the noticeable swelling found at the base of the tail of many male snakes and some lizards, caused by the presence of the hemipenes. It is one of the features experienced keepers may use when estimating the sex of an animal, although it is not always reliable and should not be used as the sole method of sexing.
Herbivore
An animal whose diet consists mainly of plant material, such as leaves, flowers and vegetables.
Herping
The hobby or activity of searching for reptiles and amphibians in their natural habitats. Herping is often carried out to observe, photograph or study wild animals without disturbing them.
Herptile
A collective term used to describe both reptiles and amphibians. The word comes from the Greek word herpeton, meaning "creeping animal."
Het (Heterozygous)
An animal carrying one copy of a recessive genetic trait without displaying it visually.
Hibernation
A period of deep dormancy experienced by some animals during cold weather. In reptiles, the correct term is usually brumation, although the two are often confused. Hibernation is more commonly associated with mammals such as hedgehogs and bats.
Homozygous
An animal that carries two identical copies of the same gene. If the gene is recessive, a homozygous animal will usually display that trait visually.
Humidity
The amount of moisture present in the air. Different reptile species require different humidity levels to remain healthy and shed properly.
Husbandry
The care and management of an animal, including its housing, diet, heating, lighting, humidity and overall welfare. Good husbandry is essential for keeping reptiles healthy.
Hygrometer
A device used to measure the humidity inside an enclosure.
I
Inclusion Body Disease (IBD)
Inclusion Body Disease (IBD) is a serious viral disease that primarily affects boas and pythons. It attacks the nervous and immune systems and can cause symptoms such as loss of coordination, unusual body movements, difficulty feeding, regurgitation and weight loss. Unfortunately, there is currently no cure, and affected snakes often have a poor prognosis.
IBD is most commonly spread through direct contact with infected snakes or by snake mites, which can carry the virus between animals. Good quarantine procedures and effective mite control are essential in helping to prevent its spread.
Incubation
Incubation is the process of keeping eggs under the correct environmental conditions so that an embryo can develop and hatch successfully. This usually involves maintaining the appropriate temperature and humidity for the species. In many reptiles, incubation temperature can also influence the sex of the hatchlings.
Insectivore
An animal that feeds primarily on insects and other invertebrates.
Instar
An instar is a stage in an invertebrate's development between two moults. Each time an animal sheds its exoskeleton, it enters the next instar.
Invertebrate (Invert)
An animal that does not have a backbone, such as spiders, scorpions, millipedes, mantises crustaceans, worms and insects.
Isopods
Small crustaceans often referred to as "woodlice" or "pill bugs". In reptile keeping they are commonly used in bioactive enclosures, where they help break down waste and decaying organic matter.
J
Juvenile
A juvenile is a young animal that has grown beyond the hatchling stage but has not yet reached adulthood or sexual maturity. Juveniles are typically larger and more established than hatchlings but are still developing and may have different care requirements from adult animals.
K
Keratin
Keratin is a strong, fibrous protein that forms the outer layer of many animals. In reptiles, keratin makes up their scales, claws, beaks and shells, helping to protect them from injury, infection and water loss. During shedding, reptiles replace the old keratin layer with a new one as they grow.
L
Lizard
A lizard is a reptile belonging to the order Squamata. Lizards are incredibly diverse, ranging from tiny geckos to large monitor lizards. Most have four legs, movable eyelids and external ear openings, although some species have lost their legs through evolution.
Locality
The geographical area where a particular animal or bloodline originates. Some species show different colours, patterns or sizes depending on their locality.
LTC (Long-Term Captive)
An animal that was originally wild caught but has lived in captivity for a significant period of time. Long-Term Captive animals are often better established than newly imported wild-caught animals and may have adapted well to captive life.
M
Metabolic Bone Disease (MBD)
A condition caused by poor calcium metabolism, often linked to inadequate UVB lighting or diet.
Metamorphosis
Metamorphosis is the process of development in which an animal changes dramatically in appearance and body structure as it grows.
There are two main types:
Complete metamorphosis – Egg → Larva → Pupa → Adult (e.g. butterflies and beetles).
Incomplete metamorphosis – Egg → Nymph → Adult (e.g. mantises, stick insects and cockroaches).
Amphibians also undergo metamorphosis, changing from aquatic larvae (such as tadpoles) into adults.
Microclimate
A microclimate is a small area within an enclosure that has different environmental conditions from the surrounding space. For example, a humid hide may create a warm, humid microclimate within an otherwise dry enclosure. Creating different microclimates allows reptiles and invertebrates to choose the conditions that best suit their needs.
Mist / Misting
Spraying water into an enclosure to increase humidity and provide drinking opportunities for species that drink water droplets from leaves or enclosure surfaces.
Morph
A naturally occurring or selectively bred colour or pattern variation within a species.
Moulting
The process of shedding the outer skin or exoskeleton. This term is most commonly used for invertebrates such as tarantulas, mantises and stick insects.
MVB (Mercury Vapour Bulb)
A Mercury Vapour Bulb (MVB) is a specialised reptile bulb that provides heat, UVA and UVB from a single lamp. They are most commonly used for diurnal reptiles and must be installed at the correct distance from the basking area.
N
Nocturnal
A species that is primarily active during the night and spends much of the day resting or hiding.
Nymph
A nymph is the immature stage of certain insects that undergo incomplete metamorphosis. Nymphs resemble miniature adults but are smaller, lack fully developed wings (if applicable), and become larger through a series of moults.
O
Omnivore
An animal that eats both animal and plant matter.
Ootheca
An ootheca is a protective egg case produced by certain invertebrates, most commonly mantises and cockroaches. It contains multiple eggs and helps protect the developing young until they hatch.
Oviparous
Animals that reproduce by laying eggs, which develop and hatch outside the mother's body.
Ovoviviparous
Animals that produce eggs, but the eggs are retained inside the mother's body until they hatch. The young are therefore born live, but receive their nutrition from the egg rather than directly from the mother.
P
Paludarium
A specialised enclosure that combines both land and water areas, allowing the keeping of semi-aquatic plants and animals in a naturalistic environment.
Parthenogenesis
Parthenogenesis is a form of reproduction where a female produces offspring without mating with a male. Although uncommon, it has been recorded in several reptile species, including some snakes and lizards, as well as many invertebrates.
Pedipalps
Pedipalps are a pair of appendages located near the mouth of arachnids. They are used for sensing the environment, handling food and, in male spiders and tarantulas, transferring sperm during mating. In scorpions, the pedipalps have evolved into the large pincers used for catching prey and defence.
Plastron
The plastron is the lower part of a turtle or tortoise's shell, protecting the underside of the body. It is joined to the upper shell (the carapace) by bridges along each side.
Poisonous
A poisonous animal contains toxins that can cause harm if it is eaten or touched. Unlike venomous animals, poisonous animals do not actively inject toxins into another animal.
Q
Quick
The quick is the soft, living tissue found inside a reptile's nail. It contains blood vessels and nerves, which is why cutting into the quick can cause pain and bleeding.
When trimming a reptile's nails, only the clear tip of the nail should be removed, taking care to avoid the quick. In animals with dark-coloured nails, the quick can be difficult to see, so extra care should be taken.
R
Reptile
A cold-blooded (ectothermic) vertebrate animal belonging to the class Reptilia. Reptiles include snakes, lizards, tortoises, turtles, crocodilians and tuataras. Most reptiles have dry, scaly skin and reproduce by laying eggs, although some species give birth to live young.
Riparian
Riparian describes an animal or habitat associated with the banks of rivers, streams or other freshwater bodies. Riparian species often rely on both land and water during their daily lives.
RUB (Really Useful Box)
A Really Useful Box (RUB) is a strong plastic storage box that many reptile keepers use as an enclosure for hatchlings, juveniles, invertebrates or quarantine animals. They are lightweight, easy to clean and can be adapted with ventilation.
S
Salamander
A salamander is an amphibian. Salamanders have long bodies, tails and smooth, moist skin. Most species spend part of their lives in water and part on land, although some are fully aquatic or fully terrestrial.
Scale
A scale is a protective covering found on the skin of reptiles, fish and some other animals. Reptile scales are made of keratin, the same material found in human fingernails and hair, and help protect the animal while reducing water loss.
Scorpling
A scorpling is a baby scorpion. Scorplings are born alive rather than hatching from eggs outside the mother's body and are carried on their mother's back until after their first moult.
Scute
A scute is a hard, keratin-covered plate found on the shells of turtles and tortoises, and on the skin of crocodilians. Scutes help protect the animal and can sometimes be used to estimate the age of younger tortoises by counting growth rings, although this is not always accurate.
Semi-Aquatic
Semi-aquatic describes an animal that spends a significant amount of time both in water and on land. These species require access to both environments to thrive.
Sexual Dimorphism
The visible physical differences between males and females of the same species. These differences may include size, colour, body shape or the presence of features such as pores, crests or spurs.
Shedding
The natural process of replacing old skin with new skin as an animal grows. Snakes usually shed their skin in one complete piece, while lizards often shed in smaller sections.
Solitary
A species that naturally lives alone rather than in groups. Most reptiles are solitary and only come together to breed.
Species
A group of animals that can naturally breed together and produce fertile offspring.
Sperm Plug
A sperm plug is a waxy or gelatinous secretion produced by some male reptiles and many invertebrates after mating. It can help prevent additional matings and may indicate that breeding has recently taken place.
Spermatheca
A spermatheca is a specialised organ found in many female invertebrates, including spiders, tarantulas and insects. It stores sperm after mating, allowing the female to fertilise her eggs weeks, months or even years later, depending on the species.
Spiderling (Sling)
A spiderling, commonly shortened to sling, is a baby spider. Within the tarantula hobby, the term sling is widely used to describe young tarantulas from the time they leave the egg sac until they are large enough to be considered juveniles. Slings are much smaller and more delicate than adult tarantulas, requiring appropriately sized enclosures and prey items.
Spinnerets
Spinnerets are small silk-producing organs located at the rear of a spider or tarantula's abdomen. They produce different types of silk used for building webs, lining burrows, creating egg sacs and leaving draglines to help the spider climb safely.
Snake
A snake is a legless reptile belonging to the order Squamata. Snakes have flexible bodies covered in scales and use their tongues to detect scents in their environment. They swallow their prey whole and can be found in a wide variety of habitats across the world.
Squamate
A squamate is any reptile belonging to the order Squamata, which includes all snakes, lizards and amphisbaenians (worm lizards). Squamates are the largest group of living reptiles and are characterised by their scaly skin and flexible jaws.
Sub-Adult
A sub-adult is an animal that has grown beyond the juvenile stage but has not yet reached full adult size or sexual maturity. Sub-adults are often close to adulthood and may begin showing adult colours, behaviours or physical characteristics, but they are still developing.
Subspecies
A population within a species that has developed distinct characteristics, usually due to geographical separation, but can still breed with other members of the same species.
Substrate
The material placed on the floor of an enclosure, such as soil, bark, sand, coco fibre or paper. Different species require different substrates.
Sucking Stomach
A sucking stomach is a specialised organ found in spiders and other arachnids. As spiders are unable to chew solid food, they first inject digestive enzymes into their prey, which break the tissues down into a liquid. The sucking stomach then pumps the liquefied food into the digestive system.
T
Tadpole
A tadpole is the aquatic larval stage of frogs and toads. Tadpoles hatch from eggs, breathe through gills and gradually develop legs and lungs before transforming into adult amphibians through a process called metamorphosis.
Tarsal Claws
Tarsal claws are the small claws found at the end of an arachnid's legs. They help spiders and tarantulas grip surfaces when climbing, walking and handling prey. Some species also have specialised hairs on their feet that allow them to climb smooth surfaces such as glass.
Terrarium
A glass or plastic enclosure designed primarily for terrestrial animals or plants. The term is often used interchangeably with vivarium, although terrariums are generally used for drier environments.
Terrestrial
A species that spends most or all of its time living on the ground rather than climbing or burrowing.
Thermal Gradient
A thermal gradient is the range of temperatures within an enclosure, allowing a reptile to move between warmer and cooler areas to regulate its body temperature. A proper thermal gradient is essential for digestion, activity, immune function and overall health. It is usually created by providing a basking area at one end of the enclosure and a cooler area at the opposite end.
Thermometer
A device used to measure the temperature within an enclosure.
Thermoregulation
The process by which reptiles control their body temperature by moving between warmer and cooler areas of their enclosure. Providing a temperature gradient allows reptiles to thermoregulate naturally.
Thermostat
A safety device that controls heating equipment by maintaining the desired temperature. Every heat source should be controlled by a suitable thermostat.
Tick
A tick is a blood-feeding arachnid. Ticks attach themselves to mammals, birds and reptiles to feed and can transmit diseases. Pet reptiles should be checked regularly for ticks, particularly if they have been housed outdoors or originate from the wild.
Tortoise
A tortoise is a land-dwelling reptile with a high-domed shell and sturdy, elephant-like legs adapted for walking. Tortoises are herbivores and should not be confused with turtles, which spend much of their lives in water.
Tuatara
A tuatara is a unique reptile found only in New Zealand. Although it resembles a lizard, it belongs to its own ancient order (Rhynchocephalia) and is more closely related to reptiles that lived alongside the dinosaurs than to modern lizards.
Turtle
A turtle is a reptile adapted for life in or around water. Most turtles have webbed feet or flippers to help them swim and spend much of their time in lakes, rivers or oceans. Unlike tortoises, turtles are generally more aquatic and have flatter, more streamlined shells.
U
UVA
Ultraviolet A light forms part of the natural light spectrum and plays an important role in reptile behaviour and wellbeing. It helps reptiles see their environment more naturally and encourages behaviours such as feeding, basking, exploring and breeding.
UVB
Ultraviolet B light enables many reptiles to produce vitamin D₃, allowing them to absorb calcium from their diet. Without appropriate UVB, many species are at risk of developing Metabolic Bone Disease (MBD).
UVC
UVC (Ultraviolet C) is the shortest wavelength of ultraviolet light and is naturally filtered out by the Earth's atmosphere before it reaches the ground. It is not beneficial for reptiles and can cause serious damage to the eyes and skin if they are exposed to it.
Unlike UVA, which encourages natural behaviours, and UVB, which enables reptiles to produce vitamin D₃, UVC should never be used in reptile lighting. Most reptile UV lamps are specifically designed to produce UVA and UVB while filtering out harmful UVC.
Urticating Hairs
Urticating hairs are tiny, barbed hairs found on the abdomen of many New World tarantulas. When threatened, the tarantula can kick these hairs into the air using its back legs as a form of defence. If they come into contact with skin, eyes or airways, they can cause irritation, itching and discomfort.
V
Venomous
A venomous animal produces venom and delivers it through a bite, sting or other specialised method. Venom is used to capture prey or defend against predators.
Vertebrate
A vertebrate is an animal that has a backbone (spine). Vertebrates include mammals, birds, reptiles, amphibians and fish. Their skeleton provides support and protects the spinal cord.
Vivarium
An enclosed habitat designed to house reptiles and other exotic animals. A vivarium recreates the animal's natural environment by providing the correct heating, lighting, humidity and furnishings.
Viviparous
Animals that give birth to live young, with the developing offspring receiving nourishment directly from the mother during pregnancy.
W
WC (Wild Caught)
An animal taken directly from the wild.
X
Y
Z
Zoologist
A scientist who studies animals, including their behaviour, biology, evolution, ecology and conservation. Zoologists may work in zoos, wildlife conservation, research, education or universities.
Sex Ratios
When keepers own multiple animals of the same species, they often use a simple numerical system to show how many males, females and unsexed animals they have. The format always consists of three numbers:
Males . Females . Unsexed
For example:
1.0.0 – One male
0.1.0 – One female
1.2.0 – One male and two females
0.0.4 – Four animals of unknown or unconfirmed sex
2.3.1 – Two males, three females and one animal of unknown sex
This format is commonly used in livestock lists, breeding records, classified adverts and collection lists to quickly identify the sexes of animals within a group.
Symbols
The symbols below are commonly used to identify the sex of reptiles and other animals:
These symbols are often used alongside the breeding notation above to quickly identify
the sex of animals.
Numbers and Symbols
Male
Female