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

Great Basin Rattlesnake - Crotalus oreganus lutosus
© Randy Bjorklund/

Written by Peralee Knight

Updated: May 2, 2023

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Getting all the way down to the top five largest (and most dangerous) snakes in California was far from easy, but we managed it! Of all of California’s 46 snake species, twelve are rattlesnakes. But only five rattlers make the top five biggest, most deadly snakes in the state, and only one can be number one! Are you ready to find out which venomous snake takes the heavyweight title for the Golden state? Let’s do it!

California is a really, really big state! Coming in second only to Texas in size and Arizona in venomous snakes, Cali has something for anyone. Even if you happen to be a rattlesnake because Cali is home to a mind-blowing 12 species! In fact, one California woman had the terrifying experience of finding over 100 rattlesnakes under her home!

However, not every rattler can take the number one place as the biggest and most deadly snake. Especially when our top pick has a real reputation for not playing nice with…well, anything!

Southwestern Speckled Rattlesnake

The Southwestern speckled rattlesnake (Crotalus mitchelli pyrrhus)

The Southwestern speckled rattlesnake is the fifth largest venomous snake in California.


SizeUp to 51 inches long
HabitatDeserts, rocky areas, scrubland
ThreatVenomous, bite is rarely fatal but can be without medical care
BehaviorModerately aggressive, highly reclusive. Most bites occur through accidental contact.

Speckled rattlesnakes are identified by their unique colors and spotted markings. Depending on the surrounding environment, they can be off-white, light brown/tan, grey, yellow, orange, red, or pink. Markings include the species’ darker speckling and rings, which go the length of the snake’s body.

In California, the southwestern speckled rattlesnake is mostly found in southern California, primarily in the southeastern region. Their unique coloring and markings can vary dramatically depending on its environment. This shy, reclusive rattlesnake species could teach us all a thing or two about camouflage!

Red Diamondback Rattlesnake

red diamond rattlesnake striking

The Red Diamondback rattlesnake is the fourth largest venomous California snake.

©Creeping Things/

SizeUp to 53 inches long
HabitatCoastal areas, scrub brush, desert
ThreatVenomous, bite can be deadly without medical care
BehaviorModerate to mildly aggressive, bites are rare compared to other species

This species has markings that mirror the western diamondback rattlesnake, except for coloration. Red diamondback rattlesnakes can be identified by their reddish-brown overall color and lighter off-white diamonds. Other markings include the black and white zebralike stripes that extend 2-3 inches above the rattle tip of their tails.

In California, the red diamondback is found in regions from the southwest corner of southern Cali to the tip of the Baja Peninsula. Though the species is listed as of Least Concern by the ICUN in 2007, the state of California is trying to change that. This change is attributed to the loss of the red diamondback’s preferred habitat in coastal scrub brush and human encroachment.

Great Basin (Western) Rattlesnake

Great Basin Rattlesnake - Crotalus oreganus lutosus

The Great Basin (Western) rattlesnake is the third largest venomous snake in California.

©Randy Bjorklund/

SizeUp to 63 inches long
HabitatGrasslands, plains, rocky outcrops, agricultural areas, stone canyons
ThreatVenomous, bites can be fatal without medical care
BehaviorMildly aggressive, will bite if threatened.

The Great Basin subspecies can be identified by its olive brown/yellowish brown/light brown, or pale gray coloring and dark blotches with a pale center. The Great Basin gopher snake is a non-venomous mimic but lacks the large triangular head, overall larger body, and distinct tail of a rattlesnake.

Western rattlesnake species are California’s most common venomous snakes. However, the Great Basin subspecies is only found in the northeastern regions of the state. This is because this subspecies is only found at or near the Great Basin, which is how it got its name!

Mohave Rattlesnake

Mojave Rattlesnake

The Mojave rattlesnake, including both of its subspecies, are the second largest venomous snake species in California.

©Creeping Things/

SizeUp to 50 inches long
HabitatDeserts, plains, grasslands
ThreatVenomous, most deadly snake in the United States
BehaviorMildly aggressive and timid, but will strike if threatened

The snake with the deadliest venom in California is the Mojave rattlesnake which can be identified by its overall brown/green coloring and dark diamond-shaped blotches over the entire body. Green tones are stronger in lower elevations, whereas brown tones are more prevalent in higher elevations. Other markings include a single white band above the rattle.

This species is the deadliest snake in the United States. This is due to dual toxins contained in Mojave rattlesnake venom, a highly deadly mixture of hemotoxins and neurotoxins. Though the Mojave’s venom is far more potent than the western diamondback, its rather shy personality makes the Mojave less dangerous.

Both subspecies of Mojave rattlesnakes are found in the state of California. The northern Mojave is common throughout the state and is light brown or tan in overall coloring. The Mojave green subspecies are only found in the Mojave desert and are, naturally, a greener hue!

Western Diamondback Rattlesnake

Western diamondback rattlesnake striking

Western diamondback rattlesnakes are the number one largest, most deadly venomous snake in California.

©Audrey Snider-Bell/

SizeUp to 72 inches long
HabitatDeserts, plains, flatlands, arid/dry locations
ThreatVenomous, bite is deadly without prompt medical treatment
BehaviorHighly aggressive, quick to bite in comparison to other rattlesnakes

The largest and most dangerous snake in California is the western diamondback rattlesnake. This snake is identified by its tan/light grey coloring and dark brown/white outlined “diamondback” pattern. Other markings include distinct black and white tail bands above the rattle.

The western diamondback is the most well-known rattlesnake wherever it is commonly found. This is largely due to its high aggression and being quick to strike, far more readily than any other rattlesnake species. In California, the western diamondback is found primarily in the southeastern regions of the state. Though the Mojave rattlesnake has a much deadlier venom strength, the western diamondback is a larger, more aggressive snake. In fact, many experts believe that this Wild West rattler may just be the meanest, most dangerous member of its already deadly family!

Summary Of The Top Five Largest (And Most Dangerous) Snakes In California

1Southwestern Speckled Rattlesnake
2Red Diamondback Rattlesnake
3Great Basin (Western) Rattlesnake
4Mohave Rattlesnake
5Western Diamondback Rattlesnake

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