Viperidae
Black-tailed Horned Pitviper
VenomousMixcoatlus melanurus

The Black-tailed Horned Pitviper (Mixcoatlus melanurus) is a venomous snake in the Viperidae family, recorded in 1 country.
If you are bitten
This is a venomous snake. Treat any bite as a medical emergency: stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to emergency care immediately. Do not apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call your local emergency number or poison center.
- Family
- Viperidae
- Danger
- high
About the Black-tailed Horned Pitviper
Common names: black-tailed horned pit viper.
Mixcoatlus melanurus is a pit viper species endemic to the mountains of southern Mexico. No subspecies are currently recognized.
Description
Adults grow to between 37.5 and 50 centimetres (14+3⁄4 and 19+5⁄8 inches) in length and have a moderately stout build. In Mexico, it is called a necazcoatl, from the Nahualt words necaztli and coatl which means "eared-serpent" referring to its "horns".
Geographic range
It is found in two Mexican states, southern Puebla and Oaxaca, at elevations of 1,600–2,400 m (5,200–7,900 ft). The type locality given is "Mexico".
Conservation status
This species is classified as Endangered (EN) on the IUCN Red List of Threatened Species with the following criteria: B1ab(iii) (v3.1, 2001). A species is listed as such when the best available evidence indicates that the geographic range, in the form of extent of occurrence, is estimated to be less than 5,000 km2 (1,900 sq mi), that estimates indicate it to be severely fragmented or known to exist at no more than 5 locations, and that a continuing decline has been observed, inferred or projected, in area, extent and/or quality of habitat. It is therefore considered to be facing a very high risk of extinction in the wild. In 2007 when it was last assessed, the population trend was down.
Behavior
Terrestrial.
Adapted from Wikipedia, available under CC BY-SA.
Frequently asked: Black-tailed Horned Pitviper
- Is the Black-tailed Horned Pitviper venomous?
- Yes. The Black-tailed Horned Pitviper (Mixcoatlus melanurus) is venomous and belongs to the Viperidae family (viper). Its bite is considered high risk to people. Treat any bite as a medical emergency.
- Is the Black-tailed Horned Pitviper poisonous?
- Snakes are venomous, not poisonous. "Poisonous" means harmful to eat or touch; "venomous" means injecting toxins through a bite. The Black-tailed Horned Pitviper is venomous, delivering venom through a bite.
- Is the Black-tailed Horned Pitviper dangerous?
- This is a venomous snake. Treat any bite as a medical emergency: stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to emergency care immediately. Do not apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call your local emergency number or poison center.
- Where does the Black-tailed Horned Pitviper live?
- The Black-tailed Horned Pitviper has verified records in 1 country, including Mexico. See the distribution section below for its full range.
If you are bitten by the Black-tailed Horned Pitviper
Do
- Get away from the snake and stay calm. Most bites worsen when people panic or try again to handle the snake.
- Call 911 or Poison Control (1-800-222-1222) right away. Antivenom works best when given early.
- Note the time of the bite and, from a safe distance, the snake's color and pattern, a phone photo is enough. Do not chase it.
- Keep the bitten limb still and at roughly heart level. Sit or lie down and limit movement.
- Remove rings, watches, and tight clothing near the bite before swelling starts.
- Gently wash the bite with soap and water and cover it with a clean, dry dressing.
Do not
- Do not cut the wound or try to suck out the venom.
- Do not apply a tourniquet or ice.
- Do not drink alcohol or caffeine.
- Do not take aspirin or ibuprofen, they can worsen bleeding. Acetaminophen is safer for pain.
- Do not try to catch or kill the snake. A dead snake can still bite by reflex.
First-aid guidance adapted from the U.S. Centers for Disease Control and Prevention (CDC NIOSH), Venomous Snakes. Educational only; always follow the instructions of emergency responders.
Where it is found
More Viperidae snakes
Classification
How scientists group this snake, from the broadest category down to the exact species. Each step narrows to its closest relatives.
- OrderThe broad group of scaled reptiles: all snakes and lizards
- Squamata
- FamilyA group of related snakes that share key traits
- Viperidae
- GenusA close-knit group of very similar species
- Mixcoatlus
- SpeciesThis exact snake, named in the two-part scientific name
- Mixcoatlus melanurus
Keep learning
- Are Snakes Dangerous? The Real Risk, in PerspectiveMost snakes are harmless and avoid people. Here is the honest picture of snakebite risk worldwide and how to lower your own.
- Snakebite First Aid: What to Do (and What Never to Do)A clear, CDC-based guide to snakebite first aid: the steps that help, the popular myths that hurt, and how to tell a serious bite from a minor one.
- Venomous vs Nonvenomous: How to Tell the DifferenceThe folk rules for telling venomous snakes apart, where each one fails, and why location-based identification beats guessing by sight.
- What to Do If You Find a SnakeFound a snake at home or on a trail? Here is how to stay calm, give it space, identify it safely, and know when to call a professional.
Distribution from GBIF & iNaturalist. Venom status per CDC. Background: Wikipedia. Informational only. Never handle a snake to identify it.







