C
Species Profile

Cat Snake

Boiga

Cat-eyed climbers of the night
reptiles4all/Shutterstock.com

Cat Snake Distribution

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Invasive Species
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A closeup of a Mediterranean cat snake shows its large, cat-like eye

At a Glance

Genus Overview This page covers the Cat Snake genus as a group. Stats below are general traits shared across the genus.
Also Known As Cat-eyed snake, Cat-eyed tree snake, Tree snake, Rear-fanged tree snake
Diet Carnivore
Activity Nocturnal+
Lifespan 9 years
Weight 2.5 lbs
Status Not Evaluated
Did You Know?

Size varies widely: adults across the genus range roughly ~0.6-2.8 m total length, though many species fall around 1-2 m.

Scientific Classification

Genus Overview "Cat Snake" is not a single species but represents an entire genus containing multiple species.

Cat snakes (genus Boiga) are mostly nocturnal, arboreal colubrid snakes distributed across South and Southeast Asia, parts of East Asia, and into Australasia (including Melanesia). Many have large eyes and vertical pupils, giving rise to the common name. They are rear-fanged (opisthoglyphous) and primarily prey on lizards, birds, and small mammals.

Kingdom
Animalia
Phylum
Chordata
Class
Reptilia
Order
Squamata
Family
Colubridae
Genus
Boiga

Distinguishing Features

  • Often vertical, cat-like pupils (especially evident at night with light)
  • Large eyes and slender, laterally compressed bodies suited for climbing
  • Rear-fanged venom delivery (generally mild to moderate effects in most species, but can be medically significant in some)
  • Nocturnal, arboreal hunting behavior

Physical Measurements

Males and females differ in size

Length
4 ft 11 in (1 ft 12 in – 9 ft 10 in)
4 ft 7 in (1 ft 8 in – 8 ft 6 in)
Weight
1 lbs (0 lbs – 3 lbs)
2 lbs (0 lbs – 6 lbs)
Tail Length
1 ft 4 in (5 in – 2 ft 6 in)
1 ft 2 in (5 in – 2 ft 6 in)
Top Speed
3 mph
Boiga: slow, arboreal or ground
Venomous

Appearance

Primary Colors
Secondary Colors
Skin Type Dry skin made of keratin with overlapping scales, usually smooth but sometimes slightly keeled. Often glossy in life. Enlarged belly scales help climbing; tail is flexible side-to-side for tree movement.
Distinctive Features
  • Cat snakes (Boiga) range about 0.6–2.8 m long, most around 1–2 m. Body is slim to somewhat thick, and many that live in trees have long tails.
  • Lifespan range: commonly ~8-20+ years (varies by species, environment, and captivity vs. wild conditions; some individuals may exceed 15 years under good captive care).
  • Eyes are typically large with vertical (cat-like) pupils-especially obvious in nocturnal/crepuscular species-contributing to the common name "cat snakes."
  • Head often distinct from neck; many species have a somewhat laterally compressed body profile, aiding movement through branches and foliage.
  • Rear-fanged (opisthoglyphous) dentition: enlarged grooved posterior maxillary teeth deliver venom/salivary secretions. Medical significance varies widely among species (from low to more serious), and they are not front-fanged like vipers or elapids.
  • Ecology/behavior generalization: predominantly nocturnal and arboreal, often hunting by slow, deliberate climbing and ambush; however, some species are more semi-arboreal or will forage on the ground, especially around human-modified habitats.
  • Diet generalization: primarily lizards (including geckos), birds (especially nestlings/eggs), and small mammals; many species shift prey with size/age and local availability. Some are notably bird-nest specialists, while others are more generalist.
  • Found from South and Southeast Asia through parts of East Asia to Australasia and Melanesia; they live in lowland rainforests, mangroves, secondary forests, plantations, and peri-urban areas, causing wide color and pattern variation.
  • Boiga species differ in defense. Many flatten the neck or body, make S-shaped strike poses, open their mouths, or give quick bites. Tree species often hide in cover. Some bite more than others.
  • Color/pattern diversity is extreme at the genus level: combinations include black-yellow banding, brown/tan with darker saddles, green leaf-mimic tones, and speckled/blotched morphs; some show strong regional polymorphism.

Sexual Dimorphism

Sexual dimorphism is generally subtle to moderate and varies among species. Many Boiga show sex-related differences primarily in proportions (tail length and overall robustness) rather than dramatic color differences; however, any dimorphism can be population- and species-dependent, and not all species show clear external differences.

  • Often relatively longer tails (more subcaudal length) and proportionally slimmer posterior body in many species, consistent with typical snake sexual dimorphism.
  • May be slightly more slender overall in some species/populations; hemipenal bulges may be detectable near tail base in mature males (handling/inspection dependent).
  • Often slightly larger-bodied or heavier at comparable lengths in some species, especially during reproductive cycles; may appear more robust through midbody.
  • Typically relatively shorter tails than males (species-dependent), with less pronounced tail-base bulging.

Did You Know?

Size varies widely: adults across the genus range roughly ~0.6-2.8 m total length, though many species fall around 1-2 m.

Most species are nocturnal and arboreal, using large eyes and vertical pupils-hence the common name "cat snake."

Boiga are rear-fanged (opisthoglyphous): enlarged grooved teeth at the back help deliver venom while holding prey.

Diet is diverse across species and habitats: many take lizards and geckos, others focus more on birds, nestlings, eggs, or small mammals.

Venom effects on humans vary by species and circumstance: many bites cause localized pain/swelling, but some species have caused more serious symptoms.

They're egg-layers (oviparous); clutch sizes vary substantially among species (often several to a few dozen eggs).

One member of the genus, the brown tree snake (Boiga irregularis), became infamous after being introduced to Guam, where it caused major ecological and economic impacts.

Unique Adaptations

  • Vertical pupils and comparatively large eyes: useful for low-light hunting; not all individuals look identical, but the "cat-eye" look is common across the genus.
  • Opisthoglyphous (rear-fanged) dentition: helps subdue prey such as lizards and birds; effectiveness and venom potency differ among species.
  • Slender, laterally compressed bodies and strong climbing ability: well-suited for moving along branches, vines, and dense shrubs.
  • Cranial and jaw flexibility typical of colubrids: allows swallowing relatively large prey items (e.g., birds or sizable lizards) compared with head width.
  • Cryptic pattern diversity: across the genus, patterns range from leaf-litter browns and greens to bold banding-supporting camouflage in different forest types and regions.

Interesting Behaviors

  • Nocturnal "branch-hunting": many Boiga move slowly along vegetation edges, pausing to watch and then striking at sleeping lizards or roosting birds.
  • Arboreal ambush at nests: several species are known to raid bird nests; some will take eggs or nestlings, while others more often target adult birds.
  • Wide prey flexibility with local specialization: in some places individuals feed mostly on geckos; elsewhere the same species (or close relatives) may switch to birds or small mammals depending on availability.
  • Defensive displays vary across the genus: common tactics include neck flattening, S-shaped striking posture, bluff strikes, and musk release; intensity varies by species and temperament.
  • Mostly solitary, but may concentrate where prey is abundant (e.g., near lights attracting geckos, or near nesting/roosting sites).
  • Habitat use is variable: many are primarily arboreal, but some species (or populations) regularly forage on the ground or around human structures at night.

Cultural Significance

Cat snakes (Boiga) are common at night in South and Southeast Asia and Australasia around trees, gardens, and houses where geckos live. Their cat-like eyes make people curious and cautious. In the Pacific, introduced brown tree snake (Boiga irregularis) caused major ecosystem change, policy debates, biodiversity loss, and infrastructure damage.

Myths & Legends

Name-and-image tradition: the widespread English name "cat snake" comes from their vertical pupils and big eyes, a long-standing natural-history association that shaped how people described them in colonial-era field accounts and later popular guides.

In Guam the introduced brown tree snake (Boiga) became an island story used to teach about bad results of people moving animals and the need for strict biosecurity; more modern tale than ancient myth.

Where Boiga live, people often include them in broader South and Southeast Asian snake traditions. They may be seen as household protectors, bad omens, forest spirits, or serpent guardians, not set apart.

Conservation Status

NE Not Evaluated (genus-level; IUCN assesses Boiga mainly at the species level-statuses span from Least Concern to threatened categories, with some Data Deficient taxa)

Has not yet been evaluated against the criteria.

Population Unknown

Protected Under

  • Protection varies by range state; some Boiga species are covered under national wildlife protection laws and regulations
  • Many populations occur within protected areas (national parks, wildlife sanctuaries, forest reserves) across South/Southeast Asia and parts of Australasia
  • Not generally listed under CITES at the genus level; any trade controls are primarily national/subnational and species-specific

You might be looking for:

Cat snakes (older broad usage)

32%

Boiga spp.

In some regions 'cat snake' is used loosely for multiple Boiga species rather than one specific species.

Brown tree snake

28%

Boiga irregularis

Well-known cat snake; invasive on Guam; nocturnal, arboreal.

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Mangrove (gold-ringed) cat snake

22%

Boiga dendrophila

Large, striking black-and-yellow Boiga from SE Asia; potent rear-fanged venom for a colubrid.

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Green cat snake

18%

Boiga cyanea

Slender green arboreal species from SE Asia; often encountered near forests and plantations.

Life Cycle

Birth 8 hatchlings
Lifespan 9 years

Lifespan

In the Wild
4–15 years
In Captivity
8–25 years

Reproduction

Mating System Polygynandry
Social Structure Solitary
Breeding Pattern Transient
Fertilization Internal Fertilization
Birth Type Internal_fertilization

In Boiga, mating is polygynandrous (both sexes mate with multiple partners). Snakes are solitary. Mating causes internal fertilization; most species lay eggs. Females can sometimes store sperm. Mating is brief and seasonal, with no parental care.

Behavior & Ecology

Social No consistent group name (usually solitary) Group: 1
Activity Nocturnal, Crepuscular, Cathemeral
Diet Carnivore Lizards (particularly geckos and other readily encountered arboreal/structure-associated lizards)
Seasonal Hibernates 3 mi

Temperament

Generally secretive and wary; many remain motionless or retreat when disturbed, relying on camouflage and arboreal escape routes.
Defensive behaviors are common when cornered: striking, persistent biting, and holding on; rear-fanged venom is primarily for subduing prey but can contribute to more confident defensive biting in some species.
Temperament varies notably among species and populations: some are relatively calm with minimal handling stress, while others are highly reactive/irritable, especially at night or when encountered in confined spaces (e.g., buildings, nest sites).
Foraging style is typically sit-and-wait or slow, deliberate active searching along branches; prey focus (lizards vs. birds vs. small mammals) can influence boldness and how readily individuals enter human-modified habitats.

Communication

hissing Defensive
Chemical communication via tongue-flicking and vomeronasal sensing; scent trails and pheromones are important for mate location and reproductive timing.
Tactile signaling during courtship (body contact, alignment, cloacal contact); likely includes subtle body positioning and sustained proximity rather than overt displays.
Visual/postural threats when disturbed: body flattening or neck expansion, S-shaped strike posture, head elevation; effectiveness may be enhanced by large eyes and head patterning in some species.
Cloacal musk release as a deterrent during handling or predation attempts.
Substrate/branch movement and occasional tail movements that may function as disturbance displays, especially in arboreal settings.

Habitat

Biomes:
Tropical Rainforest Tropical Dry Forest Savanna Temperate Forest Freshwater Wetland
Terrain:
Mountainous Hilly Plateau Plains Valley Coastal Island Riverine Karst Rocky Sandy Muddy +6
Elevation: Up to 7874 ft

Ecological Role

Nocturnal arboreal mesopredators that link canopy/understory prey communities to higher trophic levels across Asian-Australasian forest and edge ecosystems.

Regulation of small-vertebrate populations (notably lizards and rodents) Influence on bird reproductive success via predation on nests (eggs/nestlings) and roosting birds Energy transfer from arboreal/edge prey to larger predators (e.g., raptors and larger snakes) Potential suppression of pest species where rodents and commensal lizards form part of local diets

Diet Details

Main Prey:
Lizards Bird Small mammals Amphibians Other reptiles

Human Interaction

Domestication Status

Wild

Cat snakes (genus Boiga) are wild reptiles with no true domestication history. Some species are sometimes kept as pets or moved from homes. A major outlier is the brown tree snake (Boiga irregularis), which was brought to Guam, became invasive, and caused major damage to nature and buildings, shaping how people handle them.

Danger Level

Moderate
  • Rear-fanged (opisthoglyphous) venom delivery can cause medically significant local effects (pain, swelling, prolonged bleeding) in some bites; severity varies by species, individual snake, and bite circumstances.
  • Most bites occur during handling/capture; extended chewing to deliver venom increases risk-this is relevant for pet-keeping and wildlife handling.
  • Some larger species (e.g., mangrove cat snake complex) can inflict deeper bites and more pronounced symptoms; rare severe reactions are possible (including hypersensitivity).
  • Secondary risks include bacterial infection from oral flora, and falls/accidents during nocturnal encounters (arboreal snakes in homes/trees).
  • Public-health risk is generally lower than front-fanged highly venomous snakes, but not 'harmless'; clinical guidance and local medical access matter.

As a Pet

Not Suitable as Pet

Legality: Laws vary by country or state. Many places ban or limit keeping rear-fanged (venomous) snakes and may require permits. CITES and local wildlife rules differ; captive-bred availability and imports vary.

Care Level: Expert Only

Purchase Cost: $50 - $1,200
Lifetime Cost: $2,000 - $12,000

Economic Value

Uses:
Pet trade (limited/variable, often wild-caught in some markets) Scientific research (venom/toxin and ecology studies; invasive-species research for B. irregularis) Pest control/ecosystem services (predation on rodents/lizards in natural systems; context-dependent) Negative economic impact (invasive populations causing biodiversity loss, power outages, and management costs in some areas)
Products:
  • no major direct commercial products across the genus
  • research materials (venom/toxin samples; specimens for ecological and invasive-species studies)

Relationships

Related Species 8

Brown tree snake
Brown tree snake Boiga irregularis Shared Genus
Mangrove snake
Mangrove snake Boiga dendrophila Shared Genus
Green cat snake Boiga cyanea Shared Genus
Black-headed cat snake Boiga nigriceps Shared Genus
Dog-toothed cat snake Boiga cynodon Shared Genus
Flying snakes
Flying snakes Chrysopelea Shared Family
Bronzeback tree snakes Dendrelaphis Shared Family
Wolf snakes
Wolf snakes Lycodon Shared Family

Ecological Equivalents 4

Animals that fill a similar ecological role in their ecosystem

Asian vine snakes Ahaetulla spp. Overlap in habitat use (shrubs and trees), hunting style (ambush/slow stalking), and prey base (lizards and small birds). Key variation compared to Boiga: many Ahaetulla are more diurnal and more specialized on lizards.
Flying snakes
Flying snakes Chrysopelea spp. Share an arboreal life and frequently prey on geckos and other lizards, as well as nestling birds and eggs; both commonly forage along trunks and branches and around human structures. Key variation: Chrysopelea are mainly diurnal and employ gliding locomotion.
Bronzeback tree snakes Dendrelaphis spp. Arboreal, forest-edge foragers that take lizards, frogs, and small vertebrates. They co-occur across much of South and Southeast Asia and use similar forest-edge and canopy/understory strata. Key variation: Dendrelaphis species are typically fast, diurnal, and non-rear-fanged, compared with largely nocturnal, often rear-fanged Boiga.
Australasian tree snakes Dendrelaphis punctulatus In Australasia, Dendrelaphis and Boiga share tree and forest-edge habitats and feed on lizards, frogs, and small mammals. Dendrelaphis are mostly diurnal, while many Boiga are nocturnal; activity patterns and diet can vary.

Types of Cat Snake

20

Explore 20 recognized types of cat snake

Andaman cat snake Boiga andamanensis
Angle-headed cat snake Boiga angulata
Barnes' cat snake Boiga barnesii
Beddome's cat snake Boiga beddomei
Green cat snake Boiga cyanea
Dog-toothed cat snake Boiga cynodon
Mangrove snake / Gold-ringed cat snake Boiga dendrophila
Drapiez's cat snake Boiga drapiezii
Yellow cat snake Boiga flavescens
Forsten's cat snake Boiga forsteni
Gokool's cat snake Boiga gokool
Brown tree snake / Brown tree "cat snake" Boiga irregularis
Jasper cat snake Boiga jaspidea
Kraepelin's cat snake Boiga kraepelini
Many-spotted cat snake Boiga multimaculata
Black-headed cat snake Boiga nigriceps
Ochraceous cat snake Boiga ochracea
Philippine cat snake Boiga philippina
Siamese cat snake Boiga siamensis
Common cat snake Boiga trigonata

The cat snake is a capable nocturnal hunter with cat-like eyes that help them see well in the dark.

The cat snake can be defined as a loosely related group of many different species within the Colubrid family (Coluber means snake or serpent in Latin). There are so many species that they can be difficult to classify and discuss in a single article. They have a very wide geographic range and body markings. Nevertheless, there are a few general anatomical and behavior features that unite these species together.

5 Amazing Facts

  • The cat snake’s pupils will change shape depending on the time of the day. When it is daytime, their pupils will contact into narrow slits that keep out most of the light. During the nighttime, the pupils will expand into a circle and let in more light.
  • Depending on the species, the maximum clutch size of these snakes can range up to 15 eggs. These eggs can take several months to hatch. The mother may watch over and incubate the eggs until then.
  • Although capable of producing venom, these snakes don’t rely on it for self-defense. When not hunting, they spend most of their day hiding in holes and crevices to avoid predators.
  • Some cat snakes have a prehensile tail that helps them climb into trees. They hunt and sleep in this arboreal habitat.
  • Like many snakes, these snakes primarily sense the environment through scent, vibrations, and chemical cues in the environment.

Where to Find Cat Snakes

Cat snakes have a massive geographic range extending all over the Eastern Hemisphere. There are generally three types. Eurasian cat snakes of the genus Telescopus are found throughout the driest areas of southeastern Europe, southwestern Asia, and northern Africa. Old World cat snakes of the genus Boiga inhabit Southeast Asia and the Pacific region. The African cat snakes prefer the tropical rainforests and open woodlands of sub-Saharan Africa. One of the few species of these snakes that occurs in Europe is called the Soosan snake or simply the European cat snake. The Soosan snake can be found from the Balkans in the west to the Caucasian Mountains in the east.

Close up shot of the face of a European Cat Snake

The different types of cat snakes live in a wide area that extends all over the Eastern Hemisphere.

Scientific Name and Different Types of Cat Snakes

The cat eye snakes can be divided into three separate genera: Boiga, Telescopus, and Dipsadoboa. The genus Boiga is the largest and most diverse group with some 35 species; however, the origin of this scientific name is unknown. Telescopus, which means far-sighted in Greek, includes about 12 species. Dipsadoboa, which means something like “thirsty snake,” contributes another 11 species. There is a fourth genus called Leptodeira, better known as the cat-eyed snakes. Although considered to be separate from the cat snakes, they have similar cat-like eyes. All of these genera belong to the Colubrid family. This is the largest and most diverse snake family in the world.

  • BoigaThe Boiga is native to Asia, Australia, and India, but they have spread to many other parts of the world. These snakes are highly adaptable and able to survive in many varied environments and mildly venomous.
  • Telescopus – The Telescopus is found in several areas from north Eurasia, to western Africa, to Pakistan. The have a thin body that resembles a cylinder. They can be found dwelling in trees and on the ground.
  • Dipsadoboa – The Dipsadoboa is also known as Cross-barred Tree Snake. It is mostly found in different regions of Africa. They have splotches of brown skin with a spattering of white dots.
A closeup of a Mediterranean cat snake

The cat eye snakes can be divided into three separate genera: Boiga, Telescopus, and Dipsadoboa.

Population & Conservation Status

The population numbers of the cat snake have never been properly estimated, but according to the IUCN Red List, the vast majority of species are considered to be either least concern or data deficient (meaning they haven’t been properly classified yet). Only a few species like the banded green cat snake and the Andaman cat snake are endangered in any way. Habitat loss and human persecution are usually the greatest reasons for their decline, but most populations are stable or even increasing.

Appearance & Description

Although this is a very diverse and loosely related group, there are a few definitive characteristics shared by most if not all cat snakes. They are defined most of all by a long and fairly stout body with a triangular head distinct from the neck. They also have the iconic feline-like pupils for which they’re named. The short rear fangs are positioned at the back of the throat and aren’t quite as useful for biting as other types of snakes. Although some species can measure up to 9 feet long, most are usually no longer than 2 to 4 feet. They come in a diverse array of patterns and colors, but many have green, brown, or yellow skin with black or brown markings. There are some unique-looking species in this group. The mangrove snake has a black body with regular yellow rings. The green cat snake has a bright green or yellowish-green body.

Here is how to identify the cat snake:

  • Long bodies measuring up to 9 feet.
  • Triangular heads.
  • Vertical pupils.
  • Short rear fangs.
  • Green, brown, yellow, and black are the most common colors.
Closeup of a common Indian cat snake's head

Cat snakes have distinctive triangular heads and their pupils are vertical like a cat’s eye.

History and Evolution

Similar to other species of snake, cat snakes’ ancestors were actually legged reptiles, similar to lizards and reptiles that spent more time in and near water. As you might have guessed, they either lost their legs or they became vestigial, as they became more and more unused. It is interesting to imagine animals evolving to have legs and then evolving to lose them!

The Cat Snake is a good example of how much a species can evolve differently than its sister species. Usually, this is based on many factors such as food supply, predators, and climate. Animals that we see today have all adapted to their surroundings to thrive and be successful.

How Dangerous Are They?

Despite their appearance, these snakes are not very dangerous to people at all. Their venom is considered to be fairly mild, and they have trouble opening up their mouths wide enough to bite with their rear fangs. The venom can potentially cause pain, swelling, and other mild symptoms. It may be a good idea to seek medical attention, because an allergic reaction may occur. Fortunately, the venom is mostly intended to subdue prey, not defend against potential predators.

Cat Snakes’ venom is considered to be fairly mild, and they have trouble opening up their mouths wide enough to bite with their rear fangs.

Behavior & Humans

When encountered in the wild, cat snakes are more likely to run away and hide than stand their ground and bite. They tend not to be very aggressive toward people at all. Nevertheless, some species do not like being handled and may become more aggressive than others. If cornered, there is a good chance they will attempt to bite. They generally do not make good pets even when non-aggressive because they tend to be timid and fearful of people.

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Sources

  1. Briticannica / Accessed April 23, 2022
  2. Snake Facts -- Weebly / Accessed April 23, 2022
Heather Ross

About the Author

Heather Ross

Heather Ross is a secondary English teacher and mother of 2 humans, 2 tuxedo cats, and a golden doodle. In between taking the kids to soccer practice and grading papers, she enjoys reading and writing about all the animals!

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Cat Snake FAQs (Frequently Asked Questions)

Yes, but they produce only a mild type of venom.