Discover the Largest Ridgenose Rattlesnake Ever Recorded

Written by Jeremiah Wright
Updated: September 14, 2022
Image Credit Matt Jeppson/
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Deserts, mountains, and plains throughout the Western Hemisphere are home for a well-known slithering predator: the rattlesnake. There are over 24 species of this pit viper, whose namesake tail feature is made of bony segments that clack together when vibrated to produce that infamous rattle. This sound is used to warn away potential attackers and confuse prey. A rattlesnake uses a special throat opening called a glottis to emit a loud hissing sound that also indicates its hostility.

Crotalus willardi is a rattlesnake species found in the sky island regions. It’s no wonder that snake enthusiasts would want to learn more about a snake species living in isolated mountains throughout the southwestern US and Mexico. 

The ridgenose rattlesnake is the most recent species of rattlesnake discovered in the United States. It was first described in 1905 and included five subspecies. Even though it’s a relatively small snake, as you’ll see below, it’s still worthwhile to wonder which is the largest specimen ever recorded. 

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As you know, living conditions and diet can significantly influence the growth process of snakes. So, the question is if any specimen enjoyed such a good life that it grew beyond the average length of the ridgenose rattlesnake!

What are ridgenose rattlesnakes?

Arizona Ridge-nosed Rattlesnake, Crotalus willardi
Ridgenose rattlesnakes are a species of venomous pit vipers.

Matt Jeppson/

Ridgenose rattlesnakes are scientifically called Crotalus willardi. They are a species of venomous pit vipers. Pit vipers are a subfamily of venomous vipers called Crotalinae that live in Eurasia and the Americas. They have a heat-sensing pit organ, hence their name. Pit vipers, or pit adders, include lanceheads, rattlesnakes, and Asian pit vipers.

Ridgenose rattlesnakes are also called Willard’s rattlers or Willard’s rattlesnakes. The Crotalus willardi species is categorized into five subspecies:

  • Crotalus willardi amabilis (Del Nido ridgenose rattlesnake that lives in Mexico, in north-central Chihuahua);
  • Crotalus willardi meridionalis (Southern ridgenose rattlesnake that lives in Mexico, in southwestern Zacatecas, and in southern Durango);
  • Crotalus willardi obscurus (New Mexico ridgenose rattlesnake that lives in southeastern Arizona and southwestern New Mexico, as well as in northwestern Chihuahua and northeastern Sonora);
  • Crotalus willardi silus (Chihuahuan ridgenose rattlesnake that lives in eastern Sonora and in western Chihuahua);
  • Crotalus willardi willardi (Arizona ridgenose rattlesnake living in northern Sonora and southeastern Arizona). 

Ridgenose Rattlesnake habitat, appearance, and diet

Ridgenose rattlesnakes are small snakes measuring approximately 1-2 feet long (30-60 cm). The average size of the species is about 18 inches (45 cm). These snakes are usually dark brown with white horizontal stripes. They get their name from the unique ridges on each side of their noses. Also, they live in 5,500 to 9,000-foot-high habitats, such as pine woodlands in mountain canyons.

Willard’s rattlers feed on birds, lizards, small mammals, and large centipedes. In general, pit vipers are excellent hunters. They are considered ambush hunters, which means they wait for the prey to approach and then catch it.

What is the largest ridgenose rattlesnake ever recorded?

Rattlesnakes in New Mexico
The maximum length a ridgenose rattlesnake can attain is about 1.9 to 2.1 feet.

Rusty Dodson/

The maximum length a ridgenose rattlesnake can attain is about 1.9 to 2.1 feet. At the moment, there are no large specimens recorded. Also, some sources suggest that even 2 ft specimens are rare. This is odd for snake species in general.

Most species of snake have at least one specimen known as the largest, breaking the norm regarding the average size. Therefore, it is odd to see a species, albeit relatively new, without the largest recorded individual

However, if we consider the environment and living conditions of ridgenose rattlesnakes, the oddity becomes fully explainable. 

As we mentioned, the nominate subspecies (Crotalus willardi) live mainly in the sky island regions. These regions are isolated and are rarely introduced to new predators, types of food, and so on. As such, the ridgenose rattlesnake didn’t have the chance to experience diet or temperature changes that would cause abnormal growth. This is one of the main reasons there are no records of large specimens of ridgenose rattlesnakes.

Why is the ridgenose rattlesnake endangered?

Ridgenose rattlesnakes are listed as “Least Concern.” This means that the IUCN (International Union for Conservation of Nature) does not consider this species worth protecting and conserving because they are still numerous. Four of the five ridgenose rattlesnake subspecies are safe, as their vast population remains. Still, the New Mexico ridgenose rattlesnake is considered an endangered and threatened subspecies. 

There’s still a risk of a population decline, as collectors once exploited the species with the intention of being sold on commercial markets. This was due to the snake’s small size (easy to capture) and distinctive characteristics. 

This is another reason why the species couldn’t sustain the growth of a large specimen. Collectors swarmed the habitats of the ridgenose rattlesnake and destroyed them, thus limiting the suitable habitat areas for the species. 

Are ridgenose rattlesnakes venomous?

Ridgenose rattlesnakes are venomous, but their hemotoxic venom is not as dangerous to humans as it is to other animals.

Yes, ridgenose rattlesnakes are venomous, but their hemotoxic venom is not as dangerous to humans as it is to other animals. Compared to other rattlesnakes, the venom of Crotalus willardi is milder. Even though there aren’t any official ridgenose rattlesnake bite-related deaths, the wound may hurt if you get bitten. It can also cause some discomfort. We recommend checking with a doctor anyway to make sure everything’s fine. 

What is the largest species of rattlesnakes?

Large eastern diamondback rattlesnake
The largest rattlesnake species is the eastern diamondback rattlesnake.

Chase D’animulls/

The largest rattlesnake species is the eastern diamondback rattlesnake (Crotalus adamanteus). On average, it can grow up to 6 feet (1.8 m); the largest specimen recorded was 8 feet (2.4 m). Crotalus adamanteus is known as the heaviest among venomous snakes in the Americas.

The eastern diamondback is three times larger than our tiny ridgenose rattlesnake. Luckily, they live on opposite shores, so a confrontation between the two specimens is unlikely.

Interesting facts about the ridgenose rattlesnake

Since we couldn’t tell you anything impressive related to the size of the species, we decided to include in this article some interesting facts that will certainly make you appreciate this small species of snake even more.

You might even decide to take one as a pet, if possible. Due to their small size, ridgenose rattlesnakes are easy to handle.

  • The most distinctive characteristic of the species is the prominent ridge on its snout.
  • Most subspecies are active foragers, feeding mainly on birds, small mammals, lizards, arthropods, and other snakes.
  • As agile climbers, ridgenose rattlesnakes can climb into trees and track prey from high above.
  • Most subspecies are known for their impressive camouflage. They can blend in quite easily with the forest floor.
  • Subspecies can be found in habitats as high as 5,500 (1,675 m) and even 9,000 feet (2,745 m).
  • The species has a low reproductive rate, an aspect that increases the chances of extinction if conservation action and agreements are not established.

Up Next…

If you are looking for more of the largest examples and features of some of the world’s most interesting animals, you’ve come to the right place! Check out more size-based articles below.

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I hold seven years of professional experience in the content world, focusing on real estate, nature, and wildlife. Asides from writing, I enjoy surfing the internet and listening to music.

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