E
Species Profile

Eyelash Viper

Bothriechis schlegelii

Venomous lashes of the rainforest
Roy H./Shutterstock.com

Eyelash Viper Distribution

Click a location to explore more animals from that region

Loading map...

At a Glance

Wild Species
Also Known As Palm viper, Palm pit viper, Schlegel's viper, Eyebrow viper, Palm tree viper
Diet Carnivore
Activity Nocturnal+
Lifespan 10 years
Weight 0.35 lbs
Status Least Concern
Did You Know?

Adults are typically 55-82 cm total length; exceptionally large individuals up to ~118 cm have been reported (Campbell & Lamar, 2004).

Scientific Classification

A small, primarily arboreal pit viper noted for its raised, hornlike (eyelash-like) scales above the eyes and highly variable coloration (including yellow ‘oropel’ morphs). It is venomous and an ambush predator of small vertebrates.

Kingdom
Animalia
Phylum
Chordata
Class
Reptilia
Order
Squamata
Family
Viperidae
Genus
Bothriechis
Species
Bothriechis schlegelii

Distinguishing Features

  • Distinctive raised supraocular scales forming “eyelashes” above each eye
  • Heat-sensing loreal pits characteristic of pit vipers
  • Arboreal/ambush posture with prehensile tail commonly used for gripping branches
  • Extreme color polymorphism (greens, browns, reds, yellow ‘oropel’, patterned forms)

Physical Measurements

Males and females differ in size

Length
2 ft (1 ft 10 in – 2 ft 6 in)
2 ft 6 in (1 ft 12 in – 2 ft 11 in)
Weight
0 lbs (0 lbs – 0 lbs)
0 lbs (0 lbs – 1 lbs)
Tail Length
5 in (4 in – 6 in)
4 in (3 in – 6 in)
Venomous

Appearance

Primary Colors
Secondary Colors
Skin Type Dry, thick skin with keeled dorsal scales for a rough look. Raised scales above the eyes ('eyelashes'), pit viper head scales with a loreal pit, broad belly scales, and a tail able to grasp.
Distinctive Features
  • Eyelash-like supraocular scales: multiple enlarged, raised scales above each eye creating a horned/'eyelashed' profile (diagnostic appearance feature).
  • Loreal pit anatomy: a deep heat-sensing pit (infrared detection) between eye and nostril on each side, supporting nocturnal/crepuscular ambush predation on endothermic prey.
  • Head shape and eyes: broad, triangular viperid head with a narrower neck; vertical elliptical pupils typical of low-light ambush predators.
  • Arboreal build: laterally compressed body with strong climbing ability; tail is functionally prehensile for anchoring on twigs/vines during sit-and-wait hunting.
  • Ambush predator posture: commonly coils on branches with the head angled toward likely prey paths; relies on crypsis and rapid strike from a stationary position.
  • Solenoglyphous venom apparatus: long, hinged front fangs (typical Viperidae) consistent with venom delivery during a fast strike.
  • Adult size (field-reported typical range): commonly ~55-75 cm total length; females tend to reach the larger sizes within the species (reported in standard regional snake references such as Savage, 2002; Campbell & Lamar, 2004).
  • Bothriechis schlegelii (eyelash viper) shows high color variation: individuals may be green, yellow-gold, brown, orange, or red, often with variable spots or blotches—unusually high for a pit viper.

Sexual Dimorphism

Sexual dimorphism is present but subtle. Females are typically larger-bodied and heavier on average, while males are often more slender and may show proportionally longer tails (associated with hemipenes). Dimorphism is most evident in size/robustness rather than in consistent sex-specific coloration.

  • Often more slender body build relative to length.
  • Proportionally longer tail compared with females (typical of many snakes due to hemipenal structures).
  • May show a more noticeable tail-base thickening just posterior to the cloaca (hemipenal bulge) when compared side-by-side.
  • Typically larger and more robust/heavier-bodied adults on average.
  • Proportionally shorter tail compared with males.
  • Greater abdominal girth associated with reproductive capacity (gravid females appear noticeably more robust).

Did You Know?

Adults are typically 55-82 cm total length; exceptionally large individuals up to ~118 cm have been reported (Campbell & Lamar, 2004).

Newborns are about 15-20 cm long and are live-born (viviparous), not hatched from eggs (Solorzano, 2004; Campbell & Lamar, 2004).

Color polymorphism is extreme: individuals may be green, brown, gray, pinkish, banded, or nearly solid yellow; the vivid yellow individuals are widely referred to as the golden morph.

It is a true pit viper: the heat-sensing loreal pit between eye and nostril helps detect warm-blooded prey in low light (Greene, 1997).

Diet shifts with age: juveniles often take more small ectotherms (frogs/lizards), while larger adults frequently ambush birds and small mammals from vegetation (Campbell & Lamar, 2004).

Recorded longevity in human care reaches ~16 years (San Diego Zoo animal care data).

Range spans southern Mexico through Central America into northwestern South America (e.g., Colombia/Ecuador/Venezuela); it occurs from lowlands into foothills (IUCN Red List: Bothriechis schlegelii assessment).

Unique Adaptations

  • Eyelash-like supraocular scales: raised, hornlike scales above each eye can break up the head outline and may help shed debris or water in wet forest habitats; they're the species' signature field mark (Solorzano, 2004; Campbell & Lamar, 2004).
  • Loreal pit infrared sensing: detects small temperature differences, improving prey detection and strike accuracy in dim rainforest light (Greene, 1997).
  • Extreme color polymorphism (including a golden morph): multiple stable-looking color morphs provide camouflage across mossy greens, dead-leaf browns, and lichen or yellow substrates in complex rainforest microhabitats (Solorzano, 2004).
  • Strong prehensile tail and arboreal body plan: aids anchoring and balance on narrow branches during ambush and strikes (arboreal pit viper trait discussed in Greene, 1997).
  • Cryptic patterning + stillness: combination of disruptive markings and long motionless bouts reduces detection by both prey and predators (Greene, 1997).

Interesting Behaviors

  • Sit-and-wait ambush predation: often coils on a branch or in bromeliads, holding a motionless "strike-ready" posture for long periods (Greene, 1997; Campbell & Lamar, 2004).
  • Arboreal foraging at night: commonly active after dusk, moving slowly along vines and understory branches to reposition between ambush sites (field accounts summarized in Campbell & Lamar, 2004).
  • Prey handling: typically strikes, envenomates, and releases small vertebrates, then uses chemosensory tracking (tongue-flicking/Jacobson's organ) to relocate the prey (Greene, 1997).
  • Ontogenetic habitat use: juveniles may perch lower in shrub layers where small frogs and lizards are abundant; adults are frequently encountered higher in understory vegetation (pattern reported for Bothriechis in Campbell & Lamar, 2004).
  • Defensive display: may remain still and cryptic, but if threatened can inflate the body, shift into an S-curve, and deliver fast, upward strikes from elevated perches (Greene, 1997).

Cultural Significance

In Costa Rica and nearby countries, the eyelash viper (Bothriechis schlegelii) is a well-known rainforest snake, often seen on night walks, in field guides and photos. Spanish names translate to “eyelash viper,” shaping local stories.

Myths & Legends

In parts of Central America, workers and guides warn that the eyelash viper (Bothriechis schlegelii) and other tree vipers will drop from branches onto people walking under the trees.

In Mesoamerican tradition (Maya and Aztec), snakes are sacred, like the Feathered Serpent and Maya Vision Serpent, linking tree canopies, rain, life force, and spirit world, shaping views of tree‑living snakes.

The bright yellow color morph is locally known by a Spanish nickname that translates to "tinsel" or "gold leaf," referring to its golden appearance rather than a specific traditional legend.

The species name schlegelii honors 19th-century zoologist Hermann Schlegel. Museum stories say Central American collectors treated the eyelash viper as a showpiece because its horned brows and changing colors amazed new observers.

Conservation Status

LC Least Concern

Widespread and abundant in the wild.

Population Unknown

Life Cycle

Birth 8 newborns
Lifespan 10 years

Lifespan

In the Wild
6–15 years
In Captivity
10–20 years

Reproduction

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

Bothriechis schlegelii is a solitary, arboreal pit viper. Adults meet briefly to mate; reproduction is internal and viviparous. Females bear about 4–12 (sometimes up to ~20) young and provide no care. Mating is promiscuous; sperm storage is possible.

Behavior & Ecology

Social Solitary Group: 1
Activity Nocturnal, Crepuscular
Diet Carnivore Small arboreal lizards (commonly reported prey in stomach-content/field observations; e.g., anoles, Anolis spp.)

Temperament

Ambush (sit-and-wait) predator with long stationary bouts on vegetation; movement is typically limited to shifting between day-roost and night foraging perches.
Generally relies on crypsis and immobility; defensive responses escalate when approached/handled (rapid strike possible at close range).
Eyelash viper (Bothriechis schlegelii) activity changes with season and temperature: in cool or cloudy weather they may be active at dawn, dusk, or sometimes daytime to bask, but they mostly hunt at night.
Young eyelash vipers (Bothriechis schlegelii) use tail-tip movements (caudal luring) more often than adults to attract small prey, fitting their ambush hunting style.
Longevity: published wild longevity is poorly quantified; captive longevity is reported to reach at least ~16 years in husbandry records (compiled husbandry/species databases; precise peer-reviewed maxima are limited).

Communication

Hissing/expulsion of air as a defensive warning at close range Typical of viperids; noted in species accounts such as Campbell & Lamar, 2004
Chemical communication via pheromones Skin/drag trails) for mate location and reproductive condition assessment; tongue-flicking and vomeronasal organ use are primary channels (general snake communication summarized in Greene, 1997
Tactile communication during courtship Body alignment, chin-rubbing/jerking typical of pit viper courtship sequences) and during male competition when it occurs (Greene, 1997
Vibrational/substrate cues: rapid body or tail movements against vegetation can function defensively; while pit vipers lack a true rattle, vibration is a common warning display in many taxa Greene, 1997
Visual prey-attraction Caudal luring), especially in juveniles: tail-tip motion can serve as a deceptive signal to prey rather than conspecific communication (Greene, 1997; Campbell & Lamar, 2004

Habitat

Biomes:
Tropical Rainforest Tropical Dry Forest
Terrain:
Mountainous Hilly Valley Coastal Riverine
Elevation: Up to 8661 ft 5 in

Ecological Role

Arboreal mesopredator (venomous ambush predator) in Neotropical forest ecosystems

Regulates populations of small vertebrates (rodents, small birds, frogs, lizards), helping stabilize local prey communities Links arboreal and terrestrial food webs by taking prey from both strata (e.g., treefrogs/anoles and small mammals) Serves as prey for higher predators (e.g., raptors and larger snakes), contributing to trophic energy transfer Potential indirect benefit to humans via rodent suppression in disturbed/edge habitats where rodents are present

Diet Details

Main Prey:
Small mammals Small birds Lizards Frogs

Human Interaction

Domestication Status

Wild

Bothriechis schlegelii (eyelash viper) is a wild, non‑domesticated arboreal pit viper in lowland to premontane forest edges, near plantations. Kept in zoos and venom collections, sometimes captive‑bred. Adults ~55–82 cm (to ~100 cm), females often larger. Juveniles use caudal luring (tail‑tipping), raising bite risk to humans. Captive life ~10–20 years. Human interactions include bites, killing, coexistence, ecotourism, and venom research.

Danger Level

High
  • Medically significant envenomation: as a pit viper, B. schlegelii venom can cause severe local pain and swelling, blistering, tissue injury, and systemic effects (e.g., coagulopathy) requiring urgent medical care (general clinical/toxinology summaries in Campbell & Lamar, 2004; regional medical guidance varies).
  • Bites often occur when the snake is touched, handled, or accidentally contacted in vegetation (arboreal/perching behavior increases risk during harvesting, pruning, and trail-side encounters).
  • Small size does not eliminate risk: defensive strikes can occur at close range; coloration polymorphism and excellent camouflage can lead to accidental contact.
  • Handling risk is extreme for non-professionals: safe management requires specialized tools, protocols, and access to appropriate medical care/antivenom pathways.

As a Pet

Not Suitable as Pet

Legality: Laws vary by country and region. Many places ban private ownership of venomous snakes like Bothriechis schlegelii or require permits, secure cages, and escape/bite plans. Check local and import/export rules first.

Care Level: Expert Only

Purchase Cost: $200 - $1,500
Lifetime Cost: $6,000 - $25,000

Economic Value

Uses:
Ecotourism and wildlife guiding (e.g., rainforest/night-walk encounters) Zoological exhibition and environmental education Biomedical/toxinology research value (venom components) Public health costs (bite treatment/antivenom use) and occupational risk management Regulated/illegal exotic pet trade (market value varies by color morph)
Products:
  • venom samples for research and reference collections
  • inputs to antivenom research/production programs (typically via licensed institutions)
  • educational programming and zoo display value

Relationships

Predators 5

Laughing Falcon Herpetotheres cachinnans
Gray-headed Kite Leptodon cayanensis
Roadside Hawk Rupornis magnirostris
White-nosed Coati Nasua narica
Common Opossum Didelphis marsupialis

Related Species 9

Side-striped Palm Pit Viper Bothriechis lateralis Shared Genus
Black-speckled Palm Pit Viper Bothriechis nigroviridis Shared Genus
Talamanca Eyelash Pit Viper Bothriechis supraciliaris Shared Genus
Honduran Palm Pit Viper Bothriechis marchi Shared Genus
Guatemalan Palm Pit Viper Bothriechis aurifer Shared Genus
Two-striped Forest Pit Viper Bothriechis bicolor Shared Genus
Fer-de-lance
Fer-de-lance Bothrops asper Shared Family
Bushmaster
Bushmaster Lachesis muta Shared Family
Neotropical Rattlesnake Crotalus durissus Shared Family

Ecological Equivalents 5

Animals that fill a similar ecological role in their ecosystem

Green Tree Pit Viper Bothriechis lateralis Overlaps in Central American montane forests and is primarily arboreal, using sit-and-wait hunting in vegetation. Like Bothriechis schlegelii, it is a crotaline with pit organs and ambushes small vertebrates.
Black-speckled Palm Pit Viper Bothriechis nigroviridis A closely sympatric, arboreal/semi-arboreal Bothriechis in Central America; exhibits similar perch-hunting/ambush behavior and a diet focused on small frogs, lizards, birds, and rodents (Campbell & Lamar, 2004; Savage, 2002).
Two-striped Forest Pit Viper Bothriechis bicolor Ecologically similar New World arboreal pit viper: cryptic coloration, vegetation-perching ambush behavior, and predation on small vertebrates. Niche overlap occurs where their ranges approach in Central America.
Two-striped Forest Pit Viper Bothrops bilineatus Not a close relative but fills a similar role. Bothrops bilineatus is an arboreal Neotropical pit viper that hunts from vegetation and preys on small birds, lizards, frogs, and mammals—useful for comparing tree-dwelling pit viper hunting in humid forests.
Amazon Tree Boa
Amazon Tree Boa Corallus hortulanus Non-venomous arboreal, nocturnal ambush predator that fills a similar niche to Bothriechis schlegelii: it hunts small vertebrates from branches in Neotropical forests and relies on camouflage.

The eyelash viper has a distinct set of scales above their eyes that look like bold eyelashes.

The eyelash viper appears in many different colors, making it attractive to the pet trade. It gives birth to live young, carrying along the eggs for half of the year before they are born. Their lifespan is at least 10 years. Scientists have yet to determine a worldwide population.

5 Amazing Eyelash Viper Facts!

  • Since they can be bright shades of yellow and often live in banana plantations, they’ve accidentally been transported between countries with exported bananas
  • The eyelash viper is known for striking faster than almost any other snake in the world.
  • The snake is polygynous, taking more than one partner in a breeding season.
  • Baby eyelash vipers are called snakelets, and they can live independently from their parents as early as their first day of life.
  • There is no specific mating season; these snakes will mate throughout the year, carrying their eggs internally for six months before giving birth to live young.
A dangerous eyelash viper, Bothriechis schlegelii, in Costa Rican rainforest. The snake can be bold shades of green and yellow.

The eyelash viper can be colored green, yellow, brown, red, pink, or blue.

Scientific Name

The scientific name of this snake is Bothriechis schlegelii, which is meant to honor a German ornithologist and herpetologist named Hermann Schlegel.

The eyelash viper has many other names, including the eyelash pit viper, eyelash palm viper, eyelash lancehead, eyelash snake, horned palm viper, and eyelash mountain viper.

Its class is Reptilia, and it is part of the Viperidae family.

Eyelash Viper isolated against white background.

The eyelash viper’s scientific name honors German ornithologist and herpetologist Hermann Schlegel.

Evolution and Origins

The eyelash viper belongs to the Viperidae family, which fossil evidence dates back to originating in the lower Miocene 23.03 million years to 15.97 million years ago.

This viper has evolved by adapting to its environment in several ways. Its scales are rough and keeled (a ridge runs down the center), which helps it traverse the branches of its arboreal habitats. A strong prehensile tail also assists it to stay up and move about in the trees. The extended scales above its eye that give this species its common name are likely an adaptation that supplies the snake with additional camouflage as it has the effect of appearing less like a typical snake’s head, useful when ambushing prey and evading predators.

yellow viper wrapped around branch of tree

The eyelash viper’s rough scales help it stay up in branches in its arboreal habitats.

Appearance

One of the big reasons that the snake is so popular is the beautiful range of colors in which it is found. They are typically found in green, brown, yellow, or red, though they can also be found in bold colors like pink or even blue. They have subtle and sparse speckles of brown or black dots along their entire body.

It would be remiss to not mention the main reason they are called the eyelash viper. With superciliary scales above their eyes, their camouflage looks much like separate pieces of grass and foliage. Plus, like all vipers, they have large needle-like fangs that fold onto the roof of their mouth when they are not going after prey. Between the eyes and the nostrils, they have pits that sense the heat of possible meals as they go by.

How to identify an eyelash viper:

  • Green, brown, yellow, red, pink, or blue body.
  • Lightly speckled with brown or black dots.
  • Superciliary scales above their eyes that look like eyelashes.

The eyelash viper is known for its distinct set of scales that look like eyelashes.

Behavior

Typically, there is no outright aggression of the snake toward humans. In fact, the vibrant colors of this snake have led it to become a highly desired pet among consumers. The venom of the eyelash viper is incredibly dangerous, though there are some cases of a “dry bite,” which means that the snake doesn’t get the chance to release venom.

Venom: How Dangerous Are Eyelash Vipers?

Like all vipers, the snake poses a significant threat to anyone nearby. They are highly venomous, and they are known for their incredibly fast strike. They aren’t aggressive, as they see larger animals as threats, not prey. And, eyelash vipers prefer to use their bite as a way to catch their prey. However, their venom is strong enough to kill a human in some circumstances.

If an eyelash viper bites you, you need to treat it the same way that you would for any pit viper. You may not even know that you’ve been bitten right away because they don’t always leave a mark. Trouble breathing, pain, bruising, changes in heart rate, and numbness are all common symptoms. You may even have a minty, rubbery, or metallic taste in the mouth. The actual risk of death and severe symptoms depends on how much venom is released and your current health risks. If you don’t experience symptoms within 8 hours, you’ll need to watch out for the next two weeks. Luckily, about 25% of bites are dry and nothing happens. Seek out medical attention if you’re unsure.

Even if the pit viper is dead, it can still strike and release venom for up to 90 minutes, so be careful around the head.

eyelash viper wrapped on branch

Eyelash vipers are highly venomous but are not aggressive.

Habitat

The primary home of the eyelash viper is Central and South America, though it has been found as far north as southern Mexico and as far south as the lowland areas of Peru, Ecuador, and Costa Rica. They prefer a humid and tropical climate, specifically placed in lower altitudes.

With dense foliage, the viper can conceal itself within its natural habitat to protect it from being seen by predators. Yellow eyelash vipers often live in or near banana plantations. They blend into their surroundings easily and ambush prey, such as bats. Red eyelash vipers tend to be in environments where red-colored bromeliads grow, allowing them to feed on the small amphibians in the plants’ locations. No matter what location the eyelash viper is found, they need to have a nearby water source to stay hydrated. Some studies show that this snake can be found in shaded ravines as well.

The eyelash viper is arboreal, which means it likes to live in trees. Though it doesn’t typically migrate, it will go to the same spots each year that birds migrate to.

Yellow Animal – Eyelash viper

The eyelash viper lives among the trees.

Diet

The typical diet of the eyelash viper consists of small rodents, frogs, lizards, and small birds.

The eyelash viper is an ambush hunter, waiting for their prey to come by as they lay in wait. Since migratory birds tend to be on their preferred menu, these reptiles will sometimes go to the same area every spring as they expect their prey to return.

A yellow eye lash viper striking a mouse. The snake has large needle-like fangs that fold onto the roof of their mouth when they are not going after prey.

An eyelash viper shows how it strikes a mouse, one of the rodents included in its diet.

Predators and Threats

Natural predators of this snake species include badgers, cats, foxes, and hedgehogs.

The eyelash viper is at risk from humans due to habitat loss caused by deforestation and the clearing of land to use for livestock ranching and for banana plantations, particularly in Guatemala and Mexico. The snake has shown it is able to survive in some habitats after modifications.

Coiled up baby eyelash viper in Arenal Hanging Bridges Park in Costa Rica.

Eyelash vipers, here in snakelet form, are at threat from deforestation of its habitats.

Population and Conservation

While there is not a specific number of eyelash vipers noted, their population is steady.

The IUCN Red List considers them to be Least Concern, though they could progressively lose access to their natural habitat as deforestation and urbanization progress.

Similar Animals

View all 185 animals that start with E

Sources

  1. Wikipedia / Accessed March 1, 2022
  2. Animalia / Accessed March 1, 2022
  3. John Hopkins Medicine / Accessed March 1, 2022
  4. University of Michigan Health / Accessed March 1, 2022
  5. Everything Reptiles / Accessed March 1, 2022
  6. Smithsonian's National Zoo & Conservation Biology Institute / Accessed March 1, 2022
  7. The Tico Times / Accessed March 1, 2022
  8. Snake Facts / Accessed March 1, 2022
Catherine Gin

About the Author

Catherine Gin

Catherine Gin has more than 15 years of experience working as an editor for digital, print and social media. She grew up in Australia with an alphabet of interesting animals, from echidnas and funnel-web spiders to kookaburras and quokkas, as well as beautiful native plants including bottlebrushes and gum trees. Being based in the U.S. for a decade has expanded Catherine's knowledge of flora and fauna, and she and her husband hope to have a hobby farm and vegetable garden in future.

Thank you for reading! Have some feedback for us?


Eyelash Viper FAQs (Frequently Asked Questions)

An eyelash viper is a highly venomous snake that can be found in many beautiful colors, including pink, blue, yellow, red, brown, and green. This type of pit viper primarily lives in Central and South America, though it is sometimes kept as a pet. Its most notable feature is the bristly brow that looks like a pair of eyelashes, meant to help them conceal themselves while hunting.