Rattlesnake
Mexican Smallhead Rattlesnake
VenomousCrotalus intermedius
3 photographs of the Mexican Smallhead Rattlesnake. (c) Wouter Beukema, some rights reserved (CC BY).
The Mexican Smallhead Rattlesnake (Crotalus intermedius) 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 Smallhead Rattlesnake
Crotalus intermedius (common name Mexican small-headed rattlesnake) is a pit viper species found in central and southern Mexico. Like all other pit vipers, it is venomous. Three subspecies are currently recognized, including the nominate subspecies described here.
Description
This species grows to lengths of 50 to 60 cm (20 to 24 in). Males are somewhat larger than females. Klauber (1972) gives a maximum length of 57 cm (22 in), although captive specimens may grow larger.
Distribution and habitat
This snake is found in central and southern Mexico, more specifically in southeastern Hidalgo, southern Tlaxcala, northeastern and south-central Puebla, west-central Veracruz, Oaxaca (in the Sierra Juárez, Cerro San Filipe and the surrounding mountains, Sierra de Cuatro Venados, Sierra Madre del Sur, and the Sierra de Mihuatlán), and in Guerrero (in the Sierra Madre del Sur, west of Chilpancingo). A type locality was not given in the original paper, but "Mexico" is inferred from the title. Smith and Taylor (1950) restricted it to "El Limón, Totalco, Veracruz, Mexico".
Much of the range of this species consists of seasonally dry pine-oak forest, but it has also been found in cloud forest near Omilteme in Guerrero, as well as in the desert near Cacaloapan in Puebla, and Pachuca in Hidalgo. It is found at elevations between 2,000 and 3,200 m.
Conservation status
This species is classified as Least Concern on the IUCN Red List (v3.1, 2001). Species are listed as such due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend was stable when assessed in 2007.
Subspecies
Adapted from Wikipedia, available under CC BY-SA.
Frequently asked: Mexican Smallhead Rattlesnake
- Is the Mexican Smallhead Rattlesnake venomous?
- Yes. The Mexican Smallhead Rattlesnake (Crotalus intermedius) 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 Smallhead Rattlesnake poisonous?
- Snakes are venomous, not poisonous. "Poisonous" means harmful to eat or touch; "venomous" means injecting toxins through a bite. The Mexican Smallhead Rattlesnake is venomous, delivering venom through a bite.
- Is the Mexican Smallhead 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 Smallhead Rattlesnake live?
- The Mexican Smallhead 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 Smallhead Rattlesnake?
- Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
- How big does the Mexican Smallhead Rattlesnake get?
- Typically 2–5 ft; some species exceed 6 ft.
If you are bitten by the Mexican Smallhead 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 Smallhead 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.