Believe it or not, you can find EIGHT types of rattlesnakes in New Mexico!
But please don’t live in fear, thinking that you are going to be bitten. In general, rattlesnakes try to avoid any contact or interaction with people. The whole reason they have a rattle is to warn you to stay away! As long as you leave them alone, you shouldn’t have any trouble.
*If you come across any of these species, PLEASE DO NOT DISTURB! Rattlesnakes are dangerous animals and should be left alone. The more you agitate them, the more likely you could get bitten. DO NOT RELY ON THIS ARTICLE to correctly identify a rattlesnake that has recently bitten you. If you have recently been bitten, GO DIRECTLY to the nearest hospital to get help and determine if the snake is venomous.*
RELATED: The 32 Types of SNAKES Found in New Mexico! (ID Guide)
#1. Prairie Rattlesnake
- Crotalus viridis
- Adults typically range between 3.3 and 5 feet in length.
- Coloration is highly variable and can be greenish-gray, olive green, greenish-brown, light brown, or yellow. All variations have dark blotches on the body that turn into rings near the tail.
- Broad triangular head, elliptical pupils, and a tail rattle.
These rattlesnakes can be found in New Mexico in open prairies, grasslands, semi-desert shrublands, and forested environments. They can even be found at elevations up to 9500 feet (2900 m)!
The Prairie Rattlesnake hibernates during the winter, often in communal dens. These dens are typically rock crevices, caves, or old mammal burrows. Individual snakes will return to the same den each winter and migrate up to seven miles to their hunting grounds in the spring.
When they feel threatened, these snakes will freeze, using their camouflage to avoid detection. They may also quietly crawl away to cover. If approached, they may coil and rattle their tail as a warning before striking. Their potent venom has both hemotoxic and neurotoxic properties and, although rare, can be fatal to an adult human.
Prairie Rattlesnakes are listed on the ICUN Red List as a species of least concern. However, they are considered threatened and declining in parts of their range. Their biggest threats are pressures from habitat fragmentation and hunting.
#2. Western Massasauga
- Sistrurus tergeminus
- Adults range from 14 to 36 inches in length.
- Coloration is gray to light brown with dark brown blotches on the back.
- Thick body, large triangular head, heat-sensing pits between the eyes and nostrils, elliptical pupils, and rattle on the tail.
The Western Massasauga is one of the smallest rattlesnakes in the country! They primarily inhabit grassland habitats but can also be found in open sagebrush prairie, rocky hillsides, prairie hillsides, open wetlands, and grassy wetlands.
Western Massasauga Range Map
This rattlesnake is secretive and is not often seen in New Mexico.
When detected, they often freeze rather than make a rattle. However, when they do rattle, Western Massasaugas make a distinctive sound. Their rattle is significantly higher pitched than larger rattlesnakes and has earned this small snake the nickname “buzz tail.”
Though their venom is highly potent, the small quantity they deliver makes their bites much less likely to be fatal in humans than some larger rattlesnakes. However, you still need to respect them as their venom is hemotoxic and will cause localized swelling, extreme pain, and necrosis. Medical attention should be sought immediately if bitten!
#3. Western Rattlesnake
- Crotalus oreganus
- Adult size varies widely over their range, with the largest individuals being 6 feet long.
- Coloration varies greatly and can be dark brown, yellowish, dark gray, or olive-brown.
- Triangular head. A dark stripe with white borders that runs from the eye towards the jaw.
Also known as the Northern Pacific Rattle Snake, this species occupies a wide range of habitats. They can be found in mountainous areas, woodlands, and grasslands. They often occur in close proximity to humans.
Western Rattlesnakes have excellent camouflage and unique coloring, as these snakes show considerable variation. When they’re young, they have a distinct color pattern, but it fades over time as the snakes mature.
These snakes may be active during the day or night and are often curled, waiting to ambush various prey. They’ll feed on small mammals, birds, reptiles, and amphibians. They may also eat bird eggs, and young snakes often feed on insects.
Like other rattlesnakes, this species gives birth to live young. Healthy, sexually mature females can give birth to up to 25 babies!
#4. Western Diamond-backed Rattlesnake
- Crotalus atrox
- Adults typically grow to about 4 feet in length.
- Coloration ranges from brown, gray, brick red, pinkish, and chalky white. Look for the darker diamond-shaped blotches down its back, outlined by white scales.
- Broad, spade-shaped head with a black mask over the eyes.
- A rattle on the tail alternates between black and white-colored bands.
This famous rattlesnake has a wide range of habitats in New Mexico!
You might spot them in deserts, grassy plains, forested areas, rocky hillsides, or river bottoms. But your best chance to see a Western Diamond-backed Rattlesnake is probably on a rural road in the evening because of the heat the pavement retains.
Western Diamond-backed Rattlesnake Range Map
These rattlesnakes feed on small mammals such as squirrels, chipmunks, gophers, prairie dogs, rabbits, mice, and rats. They will also consume birds that fly within reach. Like other pit vipers, they bite their prey and track them while the venom takes effect.
When threatened, the Western Diamond-backed will typically stand its ground. They rattle and coil, lifting themselves off the ground to prepare to strike.
If you hear their characteristic rattle, leave the area slowly! Due to their specialized fangs and large venom glands, these Western Diamond-backed Rattlesnakes can deliver a lot of venom in a single bite! Untreated bites have a mortality rate of 10 – 20%, so make sure to get to the hospital quickly if struck!
#5. Rock Rattlesnake
- Crotalus lepidus
- Adults rarely exceed 32 inches in length.
- Robust rattlesnake with a tail rattle.
- Coloration reflects the local environment and is typically gray to green with dark brown or black banding. There may be dark speckles between the bands.
These small rattlesnakes inhabit arid habitats in New Mexico, including grasslands and mountainous areas up to 9,600 feet of elevation. They’re often spotted in rocky outcrops and rocky man-made roads. They will shelter in animal burrows, under rocks, and in or under rotting stumps and logs.
Rock Rattlesnakes are a diurnal species, which means you’re most likely to see them out during daylight hours. However, they’re somewhat secretive and hard to spot due to their excellent camouflage.
Rock Rattlesnakes primarily feed on lizards but will also consume centipedes, small mammals, birds, and other snakes when available. Like other rattlesnakes, they use their venom to subdue their prey before consuming it. In addition, their venom can cause swelling, bleeding, extreme pain, and local necrosis in humans.
Unfortunately, these rattlesnakes are often seen in the exotic animal trade for their beauty and relatively docile nature. As a result, Rock Rattlesnakes are declining and are considered threatened in parts of their range.
#6. Black-tailed Rattlesnake
- Crotalus molossus
- Adults range from 32 to 40 inches in length.
- Coloration is mixtures of yellow, olive green, brown, or black with darker blotches, diamonds, or bands with light edges.
- Distinctive uniform black or dark gray tail with a rattle.
Black-tailed Rattlesnakes inhabit deserts, grasslands, and rocky mountainous areas in New Mexico. They prefer warm and rocky areas like the sides of canyons and caves where they can easily find shelter. They hibernate in animal burrows or rock crevices during the winter.
These rattlesnakes are more likely to be seen during the day in the spring and fall. However, as the weather gets hotter in summer, they become more nocturnal to avoid the heat.
They are generally considered docile rattlesnakes, and bites to humans are very rare. In addition, they’re believed to be less toxic than other species like the Western Diamondback. However, a bite should still be treated at a hospital!
#7. Mojave Rattlesnake
- Crotalus scutulatus
- Adults range from 2 to 4 feet in length.
- Coloration is green, gray, brown, tan, or yellow with darker diamond or diamond-like markings down the back.
- Heavy-bodied, triangular head, and a white-banded rattle at the end of the tail.
Mojave Rattlesnakes are generally found in arid habitats. They prefer desert flatland with sparse vegetation, high desert, mountain slopes, grassy plains, Joshua tree woodlands, and scrub brush areas.
Mojave Rattlesnake Range Map
This species is one of the most dangerous rattlesnakes in New Mexico!
Their venom contains neurotoxins that attack the nervous system and hemotoxins that attack the blood. Mojave Rattlesnakes are ambush predators and use their camouflage to wait for unsuspecting lizards, rodents, toads, and snakes.
When disturbed, they give the characteristic tail rattle as a warning. Their potent venom means that you should give them distance and respect. If someone is bitten, chances of survival are good as long as medical attention is sought immediately.
#8. Ridge-nosed Rattlesnake
- Crotalus willardi
- Adults are only 12 to 24 inches in length.
- Coloration is typically reddish-brown to yellowish gray and matches the color of leaf litter in its habitat. White or pale horizontal striping on its body.
- Look for two white streaks beneath the eyes and a tail rattle.
These reclusive rattlesnakes are typically found in southwest New Mexico at mid to high elevations in pine, oak, and juniper woodlands. However, their limited mountainous habitat and small size mean that sightings are rare.
Ridge-nosed Rattlesnakes are threatened across most of their habitat. Fires, mining, habitat loss from cattle farming, and deforestation are all challenges. In addition, these small snakes have to deal with getting killed and collected by humans.
During the breeding season, males compete hard for mating privileges. They raise their upper bodies, intertwine, and try to press the other male to the ground. Males are opportunistic breeders, but females can be very selective. Courting and mating occur in late summer or early fall from July to August. Females typically reproduce every second or third year.
Do you need additional help identifying a rattlesnake?
I recommend purchasing a Peterson Field Guide to the Reptiles and Amphibians of North America. These books have lots of helpful information, including pictures and range maps.
Which of these rattlesnakes have YOU seen before in New Mexico?
Leave a comment below!