Rattlesnake
Mexican Pygmy Rattlesnake
VenomousCrotalus ravus
The Mexican Pygmy Rattlesnake (Crotalus ravus) is a venomous snake in the Viperidae family, recorded in 2 countries.
If you are bitten
Rattlesnake bites are medically serious. Expect intense pain, rapid swelling, and bruising. Stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to an emergency room immediately. Do NOT apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call Poison Control at 1-800-222-1222 or 911 in the US, or your local emergency number. (Source: CDC.)
- Also called
- Rattlesnake
- Family
- Viperidae
- Size
- Typically 2–5 ft; some species exceed 6 ft.
- Habitat
- Deserts, rocky outcrops, grasslands, and woodland edges, depending on species.
- Behavior
- Ambush predators that buzz the tail as a warning; mostly active in warm months and often crepuscular in summer heat.
- Identify
- Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
- Danger
- high
About the Mexican Pygmy Rattlesnake
Crotalus ravus, commonly known as the Mexican pigmy rattlesnake or Mexican pygmy rattlesnake, is a venomous pit viper species, found only in Mexico. Three subspecies are currently recognized.
Taxonomy
A study using mitochondrial DNA strongly suggests that C. ravus is part of a species complex including Crotalus triseriatus, Crotalus pusillus, Crotalus aquilus, and Crotalus lepidus. This study also confirmed strong genetic differentiation among the three subspecies aligning with geographic barriers. A follow-up study using seven nuclear markers places S. ravus basal to all other members of the species complex.
Subspecies
Description
Adults of this species usually grow to a length of 40–65 centimetres (16–26 in), but may reach more than 70 cm (28 in). They are moderately stout in build.
The distinguishing characteristics for the nominate subspecies C. r. ravus include parietal scales that are highly variable in shape and particularly large, less than 3 prefoveals, 21 midbody dorsal scales, 2–4 tail bands and a relatively large rattle.
Distribution
Found only in Mexico in the mountains in the center and south of the country, west of the Isthmus of Tehuantepec. Its range includes the southeastern part of the Mexican Plateau in the highlands of Mexico, Morelos, Tlaxcala, Puebla, Veracruz, Oaxaca, and the Sierra Madre del Sur in Guerrero. The type locality given is the "Table land of Mexico." Cochran (1961) interpreted this to be the "south tableland, Veracruz, Mexico."
Campbell and Lamar (2004) describe this species as being found across the Mexican Plateau in the temperate regions of moderate to high elevations. They estimate the vertical distribution to be from about 1,490 metres (4,890 ft) above sea level to a little over 3,000 m (9,800 ft) altitude.
Conservation
Although being listed as of "Least Concern" by the IUCN, C. ravus was listed as "threatened" by the Mexican government in 2010.
Adapted from Wikipedia, available under CC BY-SA.
Frequently asked: Mexican Pygmy Rattlesnake
- Is the Mexican Pygmy Rattlesnake venomous?
- Yes. The Mexican Pygmy Rattlesnake (Crotalus ravus) is venomous and belongs to the Viperidae family (rattlesnake). Its bite is considered high risk to people. Treat any bite as a medical emergency.
- Is the Mexican Pygmy Rattlesnake poisonous?
- Snakes are venomous, not poisonous. "Poisonous" means harmful to eat or touch; "venomous" means injecting toxins through a bite. The Mexican Pygmy Rattlesnake is venomous, delivering venom through a bite.
- Is the Mexican Pygmy Rattlesnake dangerous?
- Rattlesnake bites are medically serious. Expect intense pain, rapid swelling, and bruising. Stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to an emergency room immediately. Do NOT apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call Poison Control at 1-800-222-1222 or 911 in the US, or your local emergency number. (Source: CDC.)
- Where does the Mexican Pygmy Rattlesnake live?
- The Mexican Pygmy Rattlesnake has verified records in 2 countries, including Mexico, United States of America. See the distribution section below for its full range.
- How do I identify the Mexican Pygmy Rattlesnake?
- Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
- How big does the Mexican Pygmy Rattlesnake get?
- Typically 2–5 ft; some species exceed 6 ft.
If you are bitten by the Mexican Pygmy Rattlesnake
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
Snakes it is confused with
Gopher SnakeHarmlessRattlesnakes are sometimes confused with harmless gophersnakes/bullsnakes; only rattlesnakes have a true segmented rattle and a facial pit.
Mexican Pygmy Rattlesnake vs Gopher Snake→
More Viperidae snakes
Western RattlesnakeCrotalus oreganus
Western Diamond-backed RattlesnakeCrotalus atrox
Timber RattlesnakeCrotalus horridus
Prairie RattlesnakeCrotalus viridis
Red Diamond RattlesnakeCrotalus ruber
Mojave RattlesnakeCrotalus scutulatus
Western Black-tailed RattlesnakeCrotalus molossus
SidewinderCrotalus cerastes
Classification
How scientists group this snake, from the broadest category down to the exact species. Each step narrows to its closest relatives.
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.