C
Species Profile

Cantil

Agkistrodon bilineatus

Two stripes, one heat-seeking hunter.
J.A. Dunbar/Shutterstock.com

Cantil Distribution

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At a Glance

Wild Species
Also Known As Mexican cantil, Mexican moccasin, two-striped moccasin, two-lined moccasin, Mexican pit viper
Diet Carnivore
Activity Nocturnal+
Lifespan 10 years
Weight 2 lbs
Status Least Concern
Did You Know?

Name meaning: the species epithet means "two-lined," referring to the pale lateral stripes edged by darker pigment.

Scientific Classification

The cantil (Agkistrodon bilineatus) is a venomous New World pit viper in the family Viperidae. It is a stout-bodied, primarily terrestrial snake with heat-sensing pits used for locating prey.

Kingdom
Animalia
Phylum
Chordata
Class
Reptilia
Order
Squamata
Family
Viperidae
Genus
Agkistrodon
Species
Agkistrodon bilineatus

Distinguishing Features

  • Venomous pit viper with visible heat-sensing loreal pits
  • Stout body and relatively broad, triangular head
  • Often shows pale striping/lines along the sides (reflected in the epithet bilineatus, meaning “two-lined”)
  • Typically cryptic coloration suited to leaf litter and dry-forest substrates

Physical Measurements

Length
2 ft 7 in (1 ft 8 in – 3 ft 11 in)
Weight
2 lbs (0 lbs – 4 lbs)
Tail Length
4 in (2 in – 6 in)
Top Speed
1 mph
Slow, about 1.5 km/h
Venomous

Appearance

Primary Colors
Secondary Colors
Skin Type Dry, strongly keeled dorsal scales (matte/rough texture typical of viperids); large, plate-like head scales with small scales on crown; vertical pupils; prominent loreal heat-sensing pits between eye and nostril (pit viper trait).
Distinctive Features
  • Stout-bodied pit viper with a broad, triangular head distinct from the neck; robust build associated with ambush predation.
  • Prominent loreal heat-sensing pits (diagnostic of Crotalinae) used to detect warm-blooded prey in low light.
  • Vertical elliptical pupils; relatively short, thick tail compared with many non-viperid snakes.
  • Head often shows a dark facial mask/stripe through or behind the eye with paler lip scales (commonly described in identification accounts).
  • Typical adult total length commonly reported ~60-90 cm; larger individuals reported to about ~100-120+ cm in some references (reported maxima vary by source; see Campbell & Lamar 2004; regional guides such as Koehler 2008).
  • Mainly ground-dwelling; often found in leaf litter and rocky ground in seasonal dry habitats (dry forest and scrub) and forest edges in parts of Mexico and Central America; sits and waits to ambush prey.
  • Cantil (Agkistrodon bilineatus) is darker and heavier-bodied than many nearby snakes. It has a dark ground color with lighter crossbands and often paired lateral lines ('bi-lined').

Sexual Dimorphism

In the Cantil (Agkistrodon bilineatus), sexual differences are subtle: females are often heavier for the same length, males have longer tails (hemipenial area). Few studies give exact numbers; most reports are qualitative (e.g., Campbell & Lamar 2004).

  • Proportionally longer tail length relative to total length (typical viperid dimorphism).
  • May appear slightly more slender at comparable total length.
  • Often more robust/heavy-bodied at comparable total length (especially in gravid females).
  • Shorter tail proportion relative to total length compared with males.

Did You Know?

Name meaning: the species epithet means "two-lined," referring to the pale lateral stripes edged by darker pigment.

Typical adult total length is about 60-90 cm; large individuals are reported to reach ~120 cm total length.

Like related pit vipers such as copperheads and cottonmouths, it is live-bearing (viviparous): females give birth to fully formed young rather than laying eggs.

Its "loreal pits" detect infrared radiation, helping it aim strikes at warm prey even in low light.

Juveniles often have a brighter tail tip than adults, which can aid prey-luring (a common pit-viper tactic called caudal luring).

It is primarily terrestrial and often found under leaf litter, in rock crevices, or along brushy, rocky edges-places that match its camouflage.

The cantil is closely related to North American copperheads and cottonmouths, but occurs farther south in Mexico and Central America.

Unique Adaptations

  • Infrared "pit organ" (loreal pits) between eye and nostril, enabling detection of warm objects and improved strike accuracy in darkness.
  • Long, hinged solenoglyphous fangs (viper-style) that fold back when the mouth closes-optimized for deep venom delivery.
  • Cryptic, high-contrast striping and blotching that breaks up body outline in leaf litter and rocky scrub.
  • Robust, muscular body and keeled scales that improve traction and stability on rough ground and among stones.
  • Venom system specialized for rapid prey subjugation and digestion (typical viperid pattern), paired with a sit-and-wait hunting strategy that conserves energy.

Interesting Behaviors

  • Ambush predation: typically remains motionless in leaf litter/among rocks and strikes when prey comes within range.
  • Crepuscular to nocturnal activity is common in hot, dry habitats; may shift activity with temperature and rainfall.
  • Heat-guided targeting: combines tongue-flick chemical cues with pit-based thermal detection to orient and strike at endothermic prey.
  • Defensive repertoire: tight coiling, head elevation, open-mouth threat display, rapid strikes; may vibrate the tail in dry leaves to create an audible warning.
  • Site fidelity on a micro-scale: individuals often reuse favorable shelters (rocky cracks, root tangles) that provide stable temperature and humidity.
  • Seasonal behavior (regional): activity and breeding/birthing timing vary across its Mexico-Central America range, often tracking wet/dry seasons.

Cultural Significance

In parts of Mexico and Central America where it occurs, the cantil is widely regarded as a dangerous venomous snake and is often killed on sight, reflecting its negative cultural perception in rural areas. The species was scientifically described in 1863 by Albert Gunther.

Myths & Legends

Mesoamerican "Vision Serpent" traditions (not species-specific) depict serpents as conduits between worlds in Classic Maya art and ritual; in regions where the cantil occurs, dangerous ground-dwelling snakes are often folded into this broader sacred-serpent landscape.

In parts of Mexico and Guatemala, stories say venomous snakes like the Cantil (Cantil Pit Viper, Agkistrodon bilineatus) guard rocks, springs, and brush piles, teaching people to move stones and gather wood carefully.

Regional Spanish naming lore ties "cantil" to cliffs/rocky banks, reflecting a traditional association of the snake with stony places; this functions as a place-based warning story (the snake belongs to the rocks).

Since colonial times, rural Mesoamerican people often treated encounters with big venomous snakes like the cantil (Agkistrodon bilineatus) as signs about weather, crops, or household luck, especially near forest edges and farms.

Conservation Status

LC Least Concern

Widespread and abundant in the wild.

Population Unknown

Protected Under

  • Protected in portions of its range through national protected-area networks (occurs in multiple reserves/parks across Mesoamerica).
  • Mexico: General Wildlife Law (federal framework regulating the conservation, management, and use/possession of native wildlife).

Life Cycle

Birth 7 neonates
Lifespan 10 years

Lifespan

In the Wild 6–15 years
In Captivity 10–22 years

Reproduction

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

Few studies detail cantil (Agkistrodon bilineatus) mating. They have internal fertilization; males use hemipenes. Mating is brief with no long pair bond. Adults are solitary. No care of young; mating system uncertain.

Behavior & Ecology

Social Solitary Group: 1
Activity Nocturnal, Crepuscular
Diet Carnivore Small mammals (rodents)

Temperament

Cryptic, sedentary ambush predator; typically relies on immobility and camouflage rather than active flight when approached (Campbell & Lamar, 2004).
Defensive when threatened at close range: may coil, elevate the anterior body, gape/hiss, and strike; can stand its ground rather than flee, as commonly reported for Agkistrodon spp. (Gloyd & Conant, 1990; Greene, 1997).
Risk profile: medically significant venom; defensive behavior is context-dependent (handling, stepping near, or cornering increases strike likelihood) (Campbell & Lamar, 2004).

Communication

Hissing Defensive exhalation) during threat display (Greene, 1997; Campbell & Lamar, 2004
Chemical/pheromonal signaling detected via tongue-flicking and vomeronasal organ: mate searching and trailing, particularly during the breeding season General Agkistrodon courtship ecology summarized in Gloyd & Conant, 1990; Greene, 1997
Tactile courtship behaviors Body alignment, rubbing/pressing) during mating interactions; males may engage in ritualized combat in some viperids/Agkistrodon contexts, though species-specific rates for A. bilineatus are not well quantified in the primary literature (Greene, 1997; Gloyd & Conant, 1990
Visual/postural threat displays Coiling, head orientation toward threat); tail vibration may occur as a defensive signal in some pit vipers, but the frequency and diagnostic value for A. bilineatus specifically are not well quantified (Greene, 1997; Campbell & Lamar, 2004

Habitat

Biomes:
Tropical Dry Forest Tropical Rainforest Savanna Wetland Freshwater
Terrain:
Plains Hilly Valley Coastal Riverine Karst Rocky +1
Elevation: Up to 4921 ft 3 in

Ecological Role

Terrestrial mesopredator regulating small-vertebrate populations in Mesoamerican ecosystems (dry forest, thorn scrub, forest edge, and disturbed habitats where it persists).

Population control of small mammals (including rodent prey that can act as agricultural pests and disease reservoirs) Energy transfer from small vertebrates to higher trophic levels (as both predator and occasional prey of raptors/mammalian carnivores) Contributes to structuring local herpetofaunal and small-vertebrate community dynamics through predation pressure

Diet Details

Main Prey:
Small mammals Lizards Amphibians Small birds

Human Interaction

Domestication Status

Wild

The cantil (Agkistrodon bilineatus) is a wild, not domesticated pit viper. It has never been bred for tameness; captive snakes are kept in zoos, venom and research labs, or private collections (often illegal or by permit). People encounter them by accidental bites, killing from fear, keeping by trained handlers, venom work, and education.

Danger Level

High
  • Medically significant envenomation risk: A. bilineatus is a venomous pit viper capable of delivering defensive bites that can cause severe local pain and swelling and may produce tissue damage/necrosis and systemic effects typical of viperid envenomation (toxinology summarized in Campbell & Lamar, 2004).
  • High-risk contexts: most bites occur when the snake is handled, intentionally killed, or accidentally contacted (e.g., stepping on or reaching into cover). The species is primarily terrestrial and cryptic, increasing accidental-contact risk in its habitat.
  • Occupational exposure: elevated bite risk for field biologists, agricultural workers, snake removers, and untrained private keepers; risk is amplified by delayed access to appropriate medical care/antivenom in remote areas.
  • Public-health consequence: treatment may require hospital care and region-appropriate antivenom; delays increase severity. Handling by non-experts is strongly contraindicated.

As a Pet

Not Suitable as Pet

Legality: Cantil (Cantil Pit Viper) (Agkistrodon bilineatus) is generally not suitable or legal as a pet. Venom and laws usually require permits, a secure cage, or bans; wild capture is often illegal. Check local rules.

Care Level: Expert Only

Purchase Cost: $300 - $1,500
Lifetime Cost: $3,000 - $15,000

Economic Value

Uses:
Public health (antivenom/clinical toxinology relevance) Biomedical research (venom components) Education (zoos, outreach) Ecotourism/nature guiding Ecosystem services (rodent control)
Products:
  • venom for licensed research and antivenom production (via permitted facilities)
  • educational programming/exhibits featuring venomous snake safety

Relationships

Predators 7

Laughing Falcon Herpetotheres cachinnans
Roadside hawk Rupornis magnirostris
White-nosed coati Nasua narica
Common opossum Didelphis marsupialis
Gray four-eyed opossum Philander opossum
Central American indigo snake Drymarchon melanurus
Kingsnakes Lampropeltis spp.

Related Species 9

Copperhead Agkistrodon contortrix Shared Genus
Cottonmouth Agkistrodon piscivorus Shared Genus
Taylor's cantil Agkistrodon taylori Shared Genus
Cuban pit viper Agkistrodon russeolus Shared Genus
Fer-de-lance Bothrops asper Shared Family
Central American rattlesnake Crotalus simus Shared Family
Bushmaster Lachesis muta Shared Family
Eyelash viper Bothriechis schlegelii Shared Family
Jumping viper Atropoides nummifer Shared Family

Ecological Equivalents 4

Animals that fill a similar ecological role in their ecosystem

Fer-de-lance Bothrops asper Overlaps in Mesoamerica and plays a similar role to Agkistrodon bilineatus: a ground-dwelling ambush predator of small mammals active at night and twilight, using heat-sensing loreal pits and commonly found near forest edges and plantations.
Jumping viper Atropoides nummifer The Cantil (Agkistrodon bilineatus) is a stout, ground-dwelling pit viper inhabiting leaf litter and forest floors that ambushes small mammals, lizards, and frogs. Its short, heavy body and ambush-style behavior make it a close ecological analog.
Central American rattlesnake Crotalus simus Ground-dwelling pit viper that eats rodents and small animals, hunts by ambush using heat-sensing pits, and, though often found in open areas, functions as a mid-to-upper-level predator of small mammals in Mesoamerica.
Hognose pit viper Porthidium nasutum Small-to-medium terrestrial pit viper often found in leaf litter and forest edges. An ambush hunter that eats lizards, frogs, and small mammals, and often shares its range with larger pit vipers (e.g., Cantil, Agkistrodon bilineatus).

“Relatives of the Copperhead and the Cottonmouth”

People in the United States are familiar with the cottonmouth and the copperhead, but their close cousins, the cantils, live in south of the border in Mexico and Central America. These well-camouflaged, somewhat plumpish pit vipers are very much alike despite living miles from each other. Indeed, at one time they were all thought to be the same species. Read on for more information about the cantils.

Cantil Amazing Facts

Here are five amazing facts about cantils.

  • Cantils are ovoviviparous. This means that the cantil embryos develop in eggs, but the eggs stay inside the mother until the babies are ready to hatch.
  • Baby cantils use the tips of their tails as caudal lures. They wriggle the tip, a potential prey mistakes it for a worm, and the snake strikes when it comes close enough.
  • A good percentage of a cantil’s body is made up of its tail. The Yucatan cantil’s tail can be as much as 19.2 percent of its body length.
  • People have a great variety of names for cantils, including dimuih palka, castellana, toboba, charquera, metapil, wol-poch and uol-poch, black moccasin, Mexican moccasin and navaja.
  • A. howardgloydi, A. taylori and A. russeolus were all once considered subspecies of A. bilineatus.

Where To Find Cantils

The cantils in this article are found in Mexico and Central America. They are most often found in forests near bodies of water, though not always. A. bilineatus, the common cantil is sometimes found a good distance from water.

Cantil Scientific Name

Cantils belong to the Agkistrodon genus. Agkistrodon comes from the Greek words for “fish hook” which are ankistron and “tooth” which is odon. This most likely describes the snakes’ fangs. Bilineatus means “marked with two lines” in Latin and russeolus is Late Latin for “somewhat red.” The other two species were named in honor of people. Agkistrodon howardgloydi was named after Howard K. Gloyd, an expert on pit vipers. A. taylori was named for Edward Harrison Taylor, an American herpetologist. The name cantil comes from a Tzeltal word that means “yellow lips” which refers to the color of the lips of the Mexican cantil.

A. bilineatus has one subspecies, A. b. lemosespinali

The Different Types of Cantil

Though cottonmouths and copperheads are also part of the Agkistrodon genus, snakes known as cantils are endemic to Mexico and Central America. Cottonmouths and copperheads occur in the United States.

Agkistrodon howardgloydi can grow to a little over 37 inches. It has a ground color of reddish brown with brown cross bands. Sometimes larger males are black. There are bright lines on the sides of the head. It’s found on Nicaragua’s Pacific coast and south to northern Costa Rica.

A. bilineatus lives in Mexico and as far south as Honduras. It has a robust body and can grow to 24 inches in length. It is usually brown or black with darker bands and white accents.

A. russeolus is only found on Mexican’s Yucatan Peninsula and the northern part of Belize, and its common name is the Yucatecan cantil. It is probably the largest of the cantils and can grow to 41 inches long. It gets its name because its ground color can be a rich reddish brown. This reddish brown color has a dozen to a dozen and a half darker brown cross bands which are a lighter shade in the centers. The Yucatecan cantil has been found in limestone karst habitats where water is scarce.

A. taylori, Taylor’s cantil or the ornate cantil, is endemic to northeastern Mexico. Like A. bilineatus, it has a robust body but is smaller and grows to about 35 inches in length. It has notable stripes on its head and black or grayish brown bands over its body with yellow, orange or white accents. Males can be told from females in that they’re much darker. It is rare and considered threatened even though it lives in a variety of habitats, including forests, grasslands and thorn scrub.

Cantil Population & Conservation Status 

Though the precise number of cantils hasn’t been assessed, it is known that their numbers are declining. According to the IUCN Redlist, A. bilineatus is now considered near threatened and A. russeolus and A. howardgloydi are considered vulnerable. Only A. taylori’s status is of least concern.

How To Identify Cantils: Appearance and Description 

A cantil is a medium-sized pit viper that has a wide head and short fangs. Cantils are closely related and until genetic testing, scientists had difficulty distinguishing between them — even their venom is similar! As a result, they were all considered subspecies.

These snakes are often stocky, and most have an earth-toned ground color with 10 to 20 darker bands down their length and stripes on the head. Like other pit vipers, cantils have large scales on the flat top of their heads and heat-sensitive loreal pits between the eye and the nostril. Their eyes have vertical pupils like a cat’s. Cantils have keeled dorsal scales that number around 23 in the middle, 127 to 157 scales on the belly and 36 to 71 scales beneath the tail. All of the snakes are venomous, though they are not as aggressive as some people believe.

Cantil Venom: How Dangerous Are They?

Cantil venom is powerful and hemotoxic, which means it stops the blood from coagulating properly. The price of one bite from one of these snakes can be hemorrhaging, terrible pain, difficulty breathing, vomiting, shock, kidney failure and necrosis. In some cases the patient may die if the bite isn’t treated promptly. The good news is that usually nothing more is needed than pain control and monitoring of the patient.

Cantil Behavior and Humans

In some areas, people fear cantil snakes more than they even fear the extraordinarily venomous and aggressive fer-de-lance. Cantils pay the price for this fear as people often kill them on sight, which contributes to their population decline. Cantils tend to be actually shy and will try to avoid trouble by slithering away or staying still and hoping their colors camouflage them. If this doesn’t work, they’ll coil up, raise their tail, whip it about and gape much like the cottonmouth. They’ll strike if all else fails.

Like other snakes, cantils are carnivores and find prey through the heat sensing pits in their heads. The bite they deliver immobilizes but doesn’t necessarily kill the prey right away, and the snake takes its time to swallow it whole.

The breeding season for the snakes occurs from fall to earliest spring, and males probably engage in combat dances where they twist around each other and try to push down each other’s heads. The winner mates with the female while the loser skulks off. Hatchlings are born from May through October. The number depends on the species. Taylor’s cantil usually bears three to 11 babies while A. bilineatus can have from five to 20 snakelets. The lifespan of these snakes is from five to 10 years.

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Sources

  1. https://en.wikipedia.org/wiki/Agkistrodon
  2. https://www.centralfloridazoo.org/animals/mexican-cantil/
  3. https://nationalzoo.si.edu/animals/taylors-cantil
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5198566/

About the Author

Austin S.

Growing up in rural New England on a small scale farm gave me a lifelong passion for animals. I love learning about new wild animal species, habitats, animal evolutions, dogs, cats, and more. I've always been surrounded by pets and believe the best dog and best cat products are important to keeping our animals happy and healthy. It's my mission to help you learn more about wild animals, and how to care for your pets better with carefully reviewed products.
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Cantil FAQs (Frequently Asked Questions)

Cantils are quite venomous.

Cantils hunt by using the heat-sensing pits in their faces to detect prey. They also use a Jacobson’s organ that interprets the molecular signals from prey and lets the snake know what sort of animal they are hunting. Once they locate the prey, they lie in wait until it comes close enough to ambush. They’ll immobilize it with a bite, then swallow it. Baby cantils have brightly colored tails that they wriggle to attract prey such as frogs. The frog thinks the tip of the tail is a worm, to its detriment.

Cantils are not as aggressive as their reputation says they are, but they will make threat displays and strike if they can’t escape danger.

Cantils live in Mexico and Central America.

Their usual prey includes small mammals, birds, and their eggs as well as lizards, frogs, and fish.

A cantil is a snake in the Agkistrodon genus, particularly one that lives in Mexico and Central America.

Some people do have cantils as pets, but the trade in these snakes is illegal, and you should not have a cantil as a pet for any price. The snake is venomous and does not adapt well to captivity unless it’s in a zoo-like setting that can recreate its habitat and diet. Its unhappiness with captivity can make it unpredictable and aggressive.

Many zoos around the world have cantil snakes, including the Smithsonian National Zoo, the Central Florida Zoo, the Little Rock Zoo, and the Terra Natura Benidorm in Spain.