Discover The Top Five Largest (And Most Dangerous) Snakes In New Mexico This Summer!

Rock Rattlesnake
© Nick Kanakis/

Written by Peralee Knight

Updated: May 1, 2023

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Time to discover the top five largest (and most dangerous) snakes in New Mexico! This state is home to at least 46 species of snakes, but only eight of them are venomous. Of those eight, New Mexico’s largest venomous snakes are rattlesnakes. But which snake takes the gold for the biggest, most dangerous snake in the state? Time to find out!

The Top Five Largest (And Most Dangerous) Snakes In New Mexico

Rattlesnake species are only found in North and South America, and nearly every state has at least one rattler. New Mexico seems like the perfect place for these pit vipers, but only seven species of rattlesnakes call the state home. Of those, five species have the size and potential to be the deadliest snake in New Mexico. And the number one snake on this list has a nasty reputation!

5. The Mottled Rock Rattlesnake

Mottled Rock Rattlesnake (Crotalus lepidus)

The mottled rock rattlesnake is the fifth largest venomous snake in New Mexico.

©Rusty Dodson/

Size: Up to 30 inches long

Habitat: Rocky areas, mountain regions

Danger: Venomous, but no recorded bite deaths for the species. Bites require medical treatment to prevent infection/loss of limb.

Behavior: Highly reclusive, low aggression, but rattles in a warning.

Physical Description: Mottled rock rattlesnakes have an overall coloring that is highly specific to their environment. These colors include shades of grey, brown, white, or even blue shades that mimic rocks or stone. The mottled rock rattlesnake subspecies also have a blotchy pattern of darker markings and bands over the body.

Mottled Rock Rattlesnakes In New Mexico

This species is found in the far southeastern regions of New Mexico. Because of the species’ highly reclusive nature and habitat-specific camouflage, reports of mottled rock rattlesnake bites are rare. Additionally, while this species is quite common in the State of Texas, it is listed as Threatened in New Mexico. This classification is primarily due to loss of habitat and human encroachment in New Mexico. Mottled rock snakes in Texas are found in areas largely unaffected by humans, which leads to higher populations.  

4. The Northern Black-Tailed Rattlesnake

Black-tailed Rattlesnake

The Northern black-tailed rattlesnake is the fourth largest venomous snake in New Mexico.

©Joe McDonald/

Size: Up to 48 inches long

Habitat: Rocky locations, deserts, grasslands, boreal/high pine forests

Danger:  Venomous, bite is rarely deadly but requires medical treatment

Behavior: Mild aggression, most bites occur through accidental contact

Physical Description: Northern black-tailed rattlesnakes are brightly colored and can be yellow/yellow-green or a yellowed brown. Their chief identifying mark is the black tail tip, which ends at the rattle. Other identifiers are black diamond patterns down the back and a dark “mask” of eye markings.

Northern Black-Tailed Rattlesnakes In New Mexico

This species is found in the mountain and desert regions of southwestern and central regions of New Mexico. Northern black-tailed rattlesnakes are a subspecies of the larger black-tailed rattlesnake species classification. Other common names are the dog-headed or dog-faced rattlesnake, velvet-faced rattlesnake, or the green rattler.

3. The Prairie Rattlesnake

The Prairie rattlesnake is the third largest venomous snake in New Mexico.


Size: Up to 54 inches long

Habitat: Prairies, grasslands, flatlands

Danger: Venomous bite that can be deadly without medical care

Behavior: Moderate aggression, but will strike if threatened

Physical Description: The prairie rattlesnake has an overall brown/tan/red/orange coloring that differs depending on location. Identifiable markings are darkly outlined white blotches over the entire body and visibly textured, “pebbled” scales.

Prairie Rattlesnakes In New Mexico

This species can be found throughout New Mexico, as well as in many other southwestern U.S. states. The prairie rattlesnake is highly suited to the dry, arid environments and open landscapes found in New Mexico. However, during the hotter times of the year, prairie rattlesnakes will adjust from being active in the mornings and evenings to fully nocturnal!

2. The Mojave Rattlesnake

Mojave Rattlesnake

The Mojave rattlesnake is the most deadly snake in the United States!

©Creeping Things/

Size: Up to 54 inches long

Habitat: Deserts, grasslands, and plains

Danger: Venomous bite is highly deadly without fast medical intervention and antivenom treatment

Behavior: Low aggression, shy, timid, but will bite when threatened

Physical Description: Mojave rattlesnakes have an overall brown/green coloring and dark diamond-shaped patterns down the spine. Green hues are stronger in lower elevations, and brown hues are more prevalent in higher elevations. Another identifiable marking of the species is the white tail band ending at the rattle.

Mojave Rattlesnakes In New Mexico

This species can only be found in the extreme Southern regions of New Mexico. The Mojave rattlesnake is widely considered the snake with the deadliest bite in the United States. This is because its venom contains the most potent hemotoxins and neurotoxins of any snake species. However, even in the reclusive rattlesnake world, this species is markedly timid. But that vicious venom earns the Mojave rattlesnake the number two spot!

1. Western Diamondback Rattlesnake

Western Diamondback Rattlesnake (Crotalus atrox)

The western diamondback is the largest, most dangerous venomous snake in New Mexico!

©Alexander Wong/

Size: Up to 66 inches long

Habitat: Deserts, plains, flatlands, arid and open environments

Danger: Venomous, bite is deadly without medical intervention/antivenom treatment

Behavior: Extremely aggressive, quick to strike compared to other species

Physical Description: Western diamondbacks are tan/light grey overall, with distinct dark brown/white diamond markings down the back. Specific markings of the species are black and white banding on the tail that stops above the rattle.

Western Diamondback Rattlesnakes In New Mexico

The Western Diamondback rattlesnake is one of the most common venomous snakes in New Mexico. Due to the state’s dry, arid climate and open sandy landscape, the species can be found in every region. However, Western diamondbacks are a well-known danger nearly everywhere they are found due to their highly aggressive temperament. When it comes to the Southwestern United States, this species is nearly always the biggest and deadliest!

Mottled Rock RattlesnakeUp to 30 inches long
Northern Black-tailed RattlesnakeUp to 48 inches long
Prairie RattlesnakeUp to 54 inches long
Mojave RattlesnakeUp to 54 inches long
Western Diamondback RattlesnakeUp to 66 inches long

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