Snakes with flat triangular heads are often seen as venomous. While this isn’t necessarily false, there are other snakes with flat triangular heads that aren’t venomous.
Many flat triangular head snakes are venomous. A good percentage of triangular-head snakes have this head shape as they accommodate venom-producing glands and hollow fangs used to inject venom.
Are There Snakes with Flat Triangular (or Diamond) Heads?
Flat triangular or diamond-shaped heads are common in venomous US snakes such as pit vipers. This category of dangerous snakes includes the following types of snakes.
- Water moccasins
These are all pit vipers with heat-sensing glands. They detect mammals by heat and they all come in species with triangular heads.
Snakes have a flat triangular head to deter predators. Both venomous and non-venomous snakes have a flat head with a triangular shape.
Large venom glands can explain why venomous snakes have a triangular shape that’s wider towards the neck.
These glands are located at the back of the mouth and connected to venom ducts and the fangs in the front of the mouth.
Non-venomous snakes try to mimic flat triangular head shapes to appear venomous or more dangerous to predators.
Even snakes have plenty of predators such as hawks and eagles which eat them. Cattle are also a problem as they can kill snakes which are perceived as a threat without eating them.
Are All Snakes with Flat Triangular (or Diamond) Heads Venomous?
Snakes with flat triangular heads aren’t always venomous. While there are high chances for flat triangular head species to be venomous, these head shapes are also seen in non-venomous species.
Judging the venomous nature of a species by the shape of its head isn’t recommended. Correctly identifying venomous species by coloring, patterns, size, and habitat is recommended instead.
Venomous Snakes with Flat Triangular Heads
1. Western Rattlesnake
Scientific name: Crotalus oreganus
Common name: Western rattlesnake, (northern) Pacific rattlesnake
Western Rattlesnakes are known for their large flat triangular head and their robust body.
These venomous snakes are commonly found in Southern states. Identification is based on a long rattle and gray-brown coloring.
Western Rattlesnakes mostly come in a gray color with dark gray or brown blotches.
This snake is known for having both rectangular and diamond-shaped patterns.
Western Rattlesnakes have hemotoxic venom. This type of venom destroys tissue through catabolism and it also affects the circulatory system.
One of the worst reactions to its bite is bleeding or hemorrhaging. Left untreated, this symptom can lead to death.
2. Western Diamond-backed Rattlesnake
Scientific name: Crotalus atrox
Common name: Western diamondback rattlesnake, Texas diamond-back, adobe snake, Arizona diamond rattlesnake, coon tail, desert diamond-back, desert diamond rattlesnake, fierce rattlesnake, spitting rattlesnake, buzz tail, Texan rattlesnake, Texas rattler
This common Rattlesnake is known for its wide flattened triangular head. Western Diamond-backed Rattlesnakes have diagonal lines on their heads.
Diagonal lines run from the eyes to the jaws on the flat triangular head of the Western Diamond-backed Rattlesnake.
This sneak is also known for having diamond-shaped blotches.
Snakes of the genus are common in Arizona, New Mexico, and other Southwestern territories.
This species of snake senses heat which helps them detect possible prey.
Western Diamond-backed Rattlesnakes are sometimes killed by large animals such as cows which see them as dangerous in their habitat.
3. Eastern Copperhead
Scientific name: Agkistrodon contortrix
Common name: Eastern copperhead
Eastern Copperheads are known for having a flat triangular head. This enlarged head appears different from the rest of the body.
While it’s true many non-venomous snakes have narrow heads, the flat triangular head of the Eastern Copperhead makes it appear slightly different from other species.
Snakes of this genus are also common in Southern states, including Florida.
It lives in forests next to sources of water or swamps. It prefers woodland with leaf litter to hide in.
This snake prefers to appear flattened when in a defensive position.
4. Northern Cottonmouth
Scientific name: Agkistrodon piscivorus
Common name: Northern cottonmouth, water moccasin, swamp moccasin, black moccasin, and simply viper
Northern Cottonmouths are some of the most venomous aquatic species in the US.
These snakes have a flat triangular head and a robust heavy body that grows to a size of up to 48 inches.
These snakes are pit vipers and can sense body heat. They use body heat to detect the location of animals.
Found next to water sources, these snakes are seen throughout the year regardless of the weather.
Northern Cottonmouths are opportunistic and they do not back down from aquatic or terrestrial prey even in the winter.
Snakes of this genus are aggressive and prefer not to flee when seeing humans or potential predators.
5. Timber Rattlesnake
Scientific name: Crotalus horridus
Common name: Timber rattlesnake, canebrake rattlesnake, banded rattlesnake
Timber rattlesnakes are a venomous species. They have a large flat triangular head which is known to accommodate venom glands.
These snakes are known for their patient hunting behavior. They wait for prey to come near them before attacking.
Timber Rattlesnakes can also move toward a food source such as animal carcasses attracted to smell.
These snakes inject venom into prey quickly before starting to eat the mice or squirrels starting with the head.
Timber Rattlesnakes are known to live long lives among species with flat triangular heads as they can survive up to 25 years.
6. Prairie Rattlesnake
Scientific name: Crotalus viridis
Common name: Prairie rattlesnake, Great Plains rattlesnake
Prairies Rattlesnakes have a flat triangular head that hosts pit sensory organs. These snakes are common in the US, Canada, and Mexico.
The potent venom of Prairie Rattlesnakes should be avoided. These snakes rarely inject all venom when biting but the bite is still dangerous as the venom is both hemotoxic and neurotoxic.
Prairie Rattlesnakes are terrestrial and mainly seen on the ground. Exceptions still apply as the species can sometimes be seen up on trees.
The time of the day the snake is active depends on the weather.
It comes out during the day in the cooler months and prefers to have a nocturnal nature in the warmer summer months.
7. Broad-banded Copperhead
Scientific name: Agkistrodon laticinctus
Common name: Broad-banded copperhead, copperhead moccasin, copperhead snake, dry-land moccasin, highland moccasin, moccasin, rattlesnake pilot, red eye, Texas copperhead, thunder snake
Broad-banded Copperheads have a flat triangular head. This shape makes its head appear wider than the neck.
The snake also has cat-like eyes with elliptical pupils.
A copper-red color is specific to the species which makes its flat triangular head stand out even more.
Bites of this species are painful and dangerous. While not fatal and not as dangerous as the venom of other species, the venom of Broad-banded Copperheads still causes necrosis.
The venom is quickly delivered through its long hollow fangs.
You should avoid this species as there’s currently no antivenin made against its hemotoxic venom.
8. Florida Cottonmouth
Scientific name: Agkistrodon conanti
Common name: Florida cottonmouth
Florida Cottonmouths have a flat triangular head shape. Most other snakes that aren’t venomously found in Florida do not have a triangular head shape.
Florida Cottonmouths have a length of up to 48 inches. Snakes of this genus are known for their blotched appearance.
These snakes might also appear black with age as their color darkens through the years.
While not aggressive, these snakes can still bite when roughly handled. Immediately seeking medical attention is recommended after being bitten by the Florida Cottonmouth.
9. Mojave Rattlesnake
Scientific name: Crotalus scutulatus
Common name: Mojave rattlesnake, Mojave green
Triangular head Mojave Rattlesnakes have a large body.
This enlarged head houses one of the most dangerous types of venom Rattlesnakes can have.
Mojave Rattlesnakes are found in remote Southern locations across Arizona, California, Nevada, and other nearby arid regions.
This snake is an ambush predator coming out at night. It might be difficult to find since it has a nocturnal nature in arid habitats that aren’t inhabited.
Apart from deserts, this snake is also found in rocky areas, grasslands, shrublands, and tropical forests.
Mojave Rattlesnakes can be identified by their distinct venomous-specific diamond patterns on their backs.
10. Pygmy Rattlesnake
Scientific name: Sistrurus miliarius
Common name: pygmy rattlesnake, eastern pygmy rattlesnake, ground rattlesnake, leaf rattler, death rattler
Pygmy Rattlesnakes are a small venomous species with a flat triangular head. These snakes get their name from their short body which grows to a maximum length between 12 and 24 inches.
In the snake and animal world, pigmy describes a small stature or a short length.
These snakes have a common gray color with dark blotches and an orange stripe that runs on the central area of their backs.
These snakes can bite and their venomous bite is dangerous but not lethal.
Local tissue damage is common in the area of the bite. The bites of Pygmy Rattlesnakes need antivenom.
CroFab antivenom is given to those bitten by the snake.
11. Red Diamond Rattlesnake
Scientific name: Crotalus ruber
Common name: Red diamond rattlesnake, red rattlesnake, red diamond snake
The triangular shape head of the Red Diamond Rattlesnake is considerably wider and flatter than its body.
It’s where the venom glands are located, just behind the eyes.
Red Diamond rattlesnakes have long hollow fangs used to deliver venom.
These snakes use both smell and heat detection to find prey and possible predators to defend from.
Snakes of this genus do not readily bite people as they prefer ambushing techniques.
At the same time, these snakes open their mouths wide showing their long fangs just before they bite and inject the venom into soft tissue.
Scientific name: Crotalus cerastes
Common name: Sidewinder, horned rattlesnake, sidewinder rattlesnake, Mojave Desert sidewinder, sidewinder rattler
Sidewinders have a flat triangular-shaped head that is flat compared to the rest of their body.
These snakes are identified by a tan or light gray main color. Both the body and the flat triangular head are of a tan color.
Sidewinders have dark brown and gray marks as well as a segmented rattle at the tip of their tail.
Like other Rattlesnakes, Sidewinders have a potent venom that requires medical attention in case of a bite.
Snakes of this genus get their name from their side movements which still allow them to be fast.
Sidewinders have large scales that prevent burns on the hot desert sand they spend much of their lives on.
13. Southwestern Speckled Rattlesnake
Scientific name: Crotalus pyrrhus
Common name: Southwestern speckled rattlesnake, bleached rattlesnake, Mitchell’s rattlesnake, pale rattler, pallid rattlesnake, red rattlesnake, speckled rattlesnake, white rattlesnake
Southwestern Speckled Rattlesnakes have a flat triangular head and a length of up to 3 feet.
Snakes of this genus live in Southwestern US habitats in California, Nevada, and parts of Arizona.
These snakes are mostly associated with arid terrains, deserts, and rocky terrains.
They sometimes live in chaparral and cactus-rich terrains.
These snakes can bite even if the bite itself is not as painful as the bite of other Rattlesnakes.
Antivenom needs to be given to those bitten by a snake.
14. Eastern Diamondback Rattlesnake
Scientific name: Crotalus adamanteus
Common name: Eastern diamondback rattlesnake, eastern diamondback, diamond rattlesnake, diamond-back rattlesnake, common rattlesnake, diamond-back, diamond(-patch) rattler, diamondback rattlesnake.
This yellow, gray, and brown snake has a flat triangular head and a robust body. It can grow up to a length of 7 feet.
Eastern Diamondback Rattlesnakes inhabit various woodlands and pinelands.
The venom of the species is different from the venom of other venomous snakes in North America.
Eastern Diamondback Rattlesnakes have the most dangerous venom which can often cause severe bleeding, constant pain, and hypertension without medical intervention.
Multiple antivenins are used to combat these effects of the bite and immediate hospitalization is needed following the bite.
This type of snake isn’t typically interested in biting humans.
It feeds on rabbits and rats it finds outdoors.
15. Western Black-tailed Rattlesnake
Scientific name: Crotalus molossus
Common name: Western black-tailed rattlesnake
Western Black-tailed Rattlesnakes also have a flat triangular head. It features similar lines around its eyes which make their way down to the mouth as in other Rattlesnakes.
Like other Rattlesnakes, the Western Black-tailed Rattlesnake has diamond-shaped marks across its body and a rattle it shakes when facing danger.
This venomous species is common in California, Arizona, and other Southwestern parts of the US.
Snakes of this genus might be venomous but they also have a range of predators.
Some of these predators eat these snakes while others don’t. Cattle stamp on the snake to kill it while hawks capture the snake for food.
Since the snake is quite large as an adult (it measures up to 5 feet), predators that snatch it for food are typically interested in juvenile Western Black-tailed Rattlesnakes.
16. Eastern Black-tailed Rattlesnake
Scientific name: Crotalus ornatus
Common name: Eastern black-tailed rattlesnake
Eastern Black-tailed Rattlesnakes live in Southwestern territories.
This species has a yellow, gray, or brown color with large blotches on its back. It has a medium-sized body and its’ generally known as a calm snake.
Like the Western Black-tailed Rattlesnake, the Eastern Black-tailed Rattlesnake does not make for an easy pet to live with as it tends to live shorter lives in captivity.
This snake species is both diurnal and nocturnal with preferences for day or night depending on the season.
Eastern Black-tailed Rattlesnakes live solitary lives only meeting each other to mate.
A male that finds a suitable female partner remains with the female to disperse any other potential male prospects.
17. Rock Rattlesnake
Scientific name: Crotalus lepidus
Common name: Rock rattlesnake, green rattlesnake, blue rattlesnake, eastern rock rattlesnake, pink rattlesnake, rock rattlesnake, Texas rock rattlesnake, white rattlesnake
Found in Arizona and New Mexico, Rock Rattlesnakes have a light gray color or dark gray color with dark bands.
Coloring is mainly influenced by its habitat. Since it prefers lowland rocky terrains, this species is mostly seen in a light gray color with black bands.
This venomous pit viper has a flat triangular-shaped head.
Snakes of this genus are known for preferring to stay put when seeing people. They might bite when roughly handled but they remain passive otherwise.
These snakes might live in captivity. However, they don’t like living out of their natural habitat.
18. Western Massasauga
Scientific name: Sistrurus tergeminus
Common name: Western massasauga
Snakes of this genus are venomous. They have a flat triangular head and cat-like pupils.
This Rattlesnake has a rattle that buzzes like all other snakes of the species.
Western Massasauga snakes are also known for rattling their tails at ground level to make more noise than can make some predators step back.
Snakes of this genus are easy to spot after rain as they come out of rodent burrows looking for a dry place to rest.
They are nocturnal and not seen during the day in the summer.
Commonly inhabiting grasslands and rocky terrains, these snakes often seek shelter at or below ground level. They might enter rodent burrows during the day.
19. Tiger Rattlesnake
Scientific name: Crotalus tigris
Common name: Tiger rattlesnake
Tiger Rattlesnake also has a flat triangle head but is narrower than the head of other Rattlesnakes.
This species has crossbands and blotches.
Living solitary lives, the snakes become inactive in the coldest months of the year. It hides in burrows in December and it remains there until early February.
Tiger Rattlesnakes are agile and can sometimes be seen up on trees or even swimming, regardless of their terrestrial nature.
These snakes eat a wide range of rodents such as Kangaroo rats and mites. They can also eat lizards.
Hawks and eagles are among the predators most successful in capturing and killing Tiger Rattlesnakes.
20. Arizona Black Rattlesnake
Scientific name: Crotalus cerberus
Common name: Arizona black rattlesnake, black rattlesnake, black diamond rattlesnake, brown rattlesnake, Cerberus rattlesnake, mountain diamond-back
These snakes are also known for their spade or flat triangle-shaped heads. But the main reason people are interested in the Arizona Black Rattlesnake is its capacity to change colors.
This rare trait allows the snake to adapt its appearance depending on its mood.
Color changes are fully controlled by the species. It seems these snakes can alter their coloring differently at night compared to daytime colors as well.
21. Panamint Rattlesnake
Scientific name: Crotalus stephensi
Common name: Panamint rattlesnake, panamint rattler, Owens Valley rattler, and tiger rattlesnake
This snake is gray, brown, or tan. It has dark gray, black, or red-brown blotches similar in pattern to those on other Rattlesnakes.
These Rattlesnakes pose a serious health risk to bitten humans.
Panamint Rattlesnakes can bite and their fangs can get stuck in the soft tissue. These snakes can grow new fangs when needed.
They inject venom through the hollow fangs.
Both juveniles and adult snakes bite and medical attention is needed regardless of the age or size of the Panamint Rattlesnake.
These snakes can be aggressive and often confront other venomous snakes. They’re immune to the venom of other species.
Scientific name: Sistrurus catenatus
Common name: Massasauga, black rattler, black snapper, gray rattlesnake (Iowa), little grey rattlesnake (Canada), muck rattler, prairie rattlesnake, spotted rattler, swamp rattler, víbora de cascabel (Mexico), dwarf prairie rattlesnake, eastern massasauga great adder.
These snakes are common in forest openings and other wetlands. They live in coniferous forests and swamps.
Massasauga snakes have a flat triangle head that’s pointy at the snout and wider towards the back of the head.
These snakes are born measuring at least 7 inches. As they mature, they grow to 30 inches also adjusting their color to gray, dark gray, and gray-brown.
They then move on to areas where there’s both direct sunlight and a shaded habitat to crawl to.
Snakes of the species use a combination of open sunny habitats with shaded habitats to adjust their body temperature.
23. Ridge-nosed Rattlesnake
Scientific name: Crotalus willardi
Common name: Ridge-nosed rattlesnake, Willard’s rattlesnake, Willard’s rattler
These Rattlesnakes love to live at high altitudes. Ridge-nosed Rattlesnakes are mainly found at high altitudes in the US.
It’s here these triangle-head snakes are free to follow birds and rodents without much human interference.
These snakes aren’t as dangerous as other Rattlesnakes since they inject a small amount of venom with each bite.
Another factor that makes them less dangerous among Rattlesnakes is their removal high altitude living.
Bites are rare and they aren’t lethal.
24. Twin-spotted Rattlesnake
Scientific name: Crotalus pricei
Common name: Twin-spotted rattlesnake, western twin-spotted rattlesnake, Price’s rattlesnake, Arizona spotted rattlesnake, spotted rattlesnake, Arizona twin-spotted rattlesnake
The geographic range of the Twin-spotted Rattlesnakes is similar to the area of the Ridge-nosed Rattlesnake.
Also found in southern Arizona and further down in Mexico, this is a venomous species that grows to 24 inches.
Twin-spotted Rattlesnakes are identified by different shades of gray on their bodies. Light gray or brown-gray are combined with dark brown blotches.
These snakes are still studied today as they show a few unique traits such as maintaining higher body temperature in the case of gravid females.
Non-venomous Snakes with Flat Triangular Heads
1. Water Snakes
Scientific name: genus Nerodia
Common name: Water snakes
9 Water snakes are living in North America known for their flat triangular heads.
Species such as the Salt Marsh Snake (Nerodia clarkia) are common in North America both in the US and in Canada.
Many water snakes of the Nerodia genus are found in the Southeastern and Eastern parts of the US.
Since they live in or next to water, these snakes eat fish, amphibians, and rodents.
Scientific name: family Pythonidae
Common name: Pythons
Pythons in the US such as the Burmese Python are also known for having a flat triangle head.
The pointy snout and the wider head towards the neck are characteristic of these very large snakes.
Burmese Pythons are found in Florida where they escaped captivity and started to breed in high numbers.
Burmese Pythons are also a species of triangle snakes that use constriction to immobilize prey.
3. Corn Snakes
Scientific name: Pantherophis guttatus
Common name: Corn snakes
Corn snakes are present in Southeast US territories. These snakes can mimic a flat triangle head to appear more dangerous.
However, these snakes aren’t venomous. They only try to mimic venomous species such as Copperheads.
These snakes are known for their high numbers in corn and grain storage facilities where they feed on rodents.
4. Rat Snakes
Scientific name: genus Elaphe
Common name: Rat snakes
Rat snakes can grow up to 5 feet. These snakes also have a flat triangular head but have no venom.
They come in various colors from uniform black to olive and black striped patterns.
Rat snakes are a common species in Southeastern and Midwestern states.
They have a similar diet to venomous triangular head species which includes rodents and small mammals.
5. Garter Snakes
Scientific name: genus Thamnophis
Common name: Garter snakes
Garter snakes such as the Narrow-Headed Garter snake also have a flat triangle-shaped head.
These snakes are aquatic and spend most of their lives in water. Their diet is impacted by their habitat as they mostly eat small fish.
Gray, green, or brown, these snakes show irregular brown spots and white lateral bands next to the mouth.
6. Gopher Snake
Scientific name: Pituophis catenifer
Common name: Gopher snake, Pacific gopher snake, coast gopher snake, western gopher snake, bullsnake, Churchill’s bullsnake, Oregon bullsnake.
Found in tan, green, or yellow colors, Gopher snakes are sometimes mistaken for venomous species due to their triangular heads.
This snake eats small mammals and birds.
It also uses constriction to suffocate its prey.
Constriction might make it different from other species but its coloring and dorsal patterns as well as a triangular head often make people mistake Gopher snakes for Rattlesnakes.
What to Do When You See a Flat Triangular Head Snake
Snakes are best left alone and not handled directly when encountered out in nature.
This applies to both venomous and non-venomous snakes. Non-venomous snakes can also bite.
However, not all snakes pose a similar level of threat and you might want to stay clear of venomous snakes altogether.
Identify its venomous nature
Identifying venomous from non-venomous snakes is the key to knowing how to react to the encounter.
You might need to know which snake bit you for correct species identification if hospitalization is needed.
Assessing a species by its behavior is one of the most important aspects to keep in mind when encountering a snake.
Some of the most dangerous snakes such as Copperheads stand their ground without backing up. This might be a sign of a venomous snake encounter.
Other snakes such as rattlesnakes shake their tails in the air or on the ground as a warning sign and as a first technique to keep you away before biting.
Some snakes might even play dead. These are species that remain motionless and wait for you to move along.
The areas where you see the snake are also very important in determining its threat level. Some of the most dangerous venomous snakes such as Cottonmouths live near water.
You know that you have higher chances of encountering Cottonmouths when moving along water sources.
Others such as the Mojave Rattlesnake are only found around the Mojave Desert and arid areas nearby.
The color of the snake might also indicate its venomous nature. However, colors alone aren’t sufficient to show which snakes are venomous since they can be quite similar in some cases.
Uniform black snakes can be both venomous and non-venomous. Colors and patterns (such as Rattlesnake diamond patterns) can indicate the venomous nature of a species together with its shape, size, and habitat.
The pupils of venomous snakes often resemble cat pupils. A thin vertical stripe symbolizes the eyes of venomous snakes.
Round pupils are normally associated with non-venomous snakes which is why the shape of the pupils needs to be taken into account to know how to react.
Many venomous snakes have flat triangle-shaped heads. While this is not a sufficient characteristic to find out which species is venomous and which isn’t, it can be considered together with all other characteristics.
Refrain from handling venomous and non-venomous snakes
Once you identify venomous snakes you know you need to back away. You should also avoid non-venomous snakes as they can have a painful bite as well.
However, some venomous snakes can cause severe bleeding, nausea, and even death if their bite is left untreated. It’s best to stay further away from these species.
Leave the snakes alone and move along slowly
Once you identify a snake is best to slowly back away to be on your way. Moving along trails is often recommended when camping or hiking as many snakes are found in dense vegetation.
Some snakes are even found in the vegetation above the water, as in the case of water snakes.
Riparian zones or areas around water with vegetation have specific snakes which you need to know might be venomous or non-venomous.
Don’t follow snakes
Snakes don’t attack people directly without provocation. You might need to move along in a different direction when the snake tries to move away as the snake might bite thinking you’re following it.
Look for signs of poisoning in case of a bite.
You need to remember what the snake that bit you looked like for the antivenin and other medical treatments. If you cannot remember the appearance of the snake you need to look for venomous bite symptoms.
Necrosis around the bitten area, nausea, blurred vision, and fever are clear signs of a venomous bite. If you show such symptoms it’s time to go to the nearest hospital.
Snakes with flat triangular heads are identified by a shape that looks like a triangle. The tip of the triangle is the snout while the base is the back of the head towards the neck.
The neck of a triangular head snake is narrower than its head. Non-venomous snakes have a narrow head that is comparable in width to the neck.
Snakes with triangular heads may or may not be venomous which means you need to stay clear regardless of their nature.
Solely basing identification of these snakes based on the shape of the head and color isn’t recommended as coloring can be deceiving as well. Coral snakes and Milksnakes look similar but one is venomous while others aren’t.
You can further identify if a snake with a triangular head is venomous by the way it moves. Venomous aquatic snakes swim at the surface of the water with their bodies completely above the water.
Non-venomous aquatic snakes with triangular heads swim with their bodies mostly submerged.
In most cases, snakes with triangular heads turn out to be venomous