Snakes are some of the most frequently observed animals around us and we are fascinated by them; you might think we’d be pretty good at identifying these common reptiles by now. That’s not the case.
In Georgia alone (where I live), you can find more than 40 different species of snakes and they come in a wide variety of shapes, sizes, and habits. But regardless of their true identities, many snakes are likely to be mistaken for just a handful of widely-known species, like the copperhead and the cottonmouth.
I think there are a couple different explanations for this phenomenon. For one, copperheads and cottonmouths benefit from high name recognition, much more so than, for example, the southeastern crowned snake or striped crayfish snake. Also, many people tend to err (or panic) on the side of caution and believe that just about any snake they see is a venomous one. Coral snakes are pretty distinguishable, and so are rattlesnakes (thanks to their rattle), so cottonmouths and copperheads represent the only other potentials when it comes to venomous snakes in the United States.
I’ve been called the Best Biologist on Twitter because I spend a lot of time there identifying snakes for people; in many cases this requires me to tell them that no, the snake they found was actually #NotACopperhead. In fact, I recently turned the most common myths and misconceptions I have heard about snakes into a book: Secrets of Snakes: the Science beyond the Myths.
In this post I am going to explain how to distinguish copperheads and cottonmouths from each other as well as from a variety of other species. As a primer, here’s how I introduce the section about snake identification in my book.
“…people are always asking me for shortcuts when it comes to identifying snakes, particularly when it comes to distinguishing between venomous and nonvenomous species. I understand why; it is tempting to gravitate toward quick and easy ways to learn. I know we want rules. I know we want to be able to define a venomous snake based on the shape of its head, or the way it swims, or the order of the colored bands on its body.
But nature is too complicated and messy for reliable shortcuts. We can talk about general patterns, but these are just rules of thumb and may not even be relevant depending on what snake you are looking at or where you live….
I like to make the analogy that recognizing snakes is a lot like recognizing family and friends. You would not measure the length of Uncle Michael’s mustache to figure out who he is or examine the color patterns of Aunt Rochelle’s highlights before you gave her a hug; you just look at them and you know who they are! Identifying animals is similar; once you know them well enough, you can recognize them at a glance. Focusing on specific features may be helpful when you are first learning your snakes, but they should be considered only one step toward achieving the ability to identify them.
Another important thing to consider is that Uncle Michael’s mustache is probably useful for telling him apart from Aunt Rochelle, but it is not a useful tip for distinguishing him from all the other people in the world. It’s the same for snakes: some tips may be useful for distinguishing between two specific species, but that same tip may not be useful for distinguishing a snake from all other species.”*
Given my general philosophy on snake identification, let’s take a look at cottonmouths (Agkistrodon piscivorus) and copperheads (Agkistrodon contortrix) because these two species are frequently mistaken for each other.
They are closely related so they have a lot of things in common, like vertical pupils and heat-sensing pits, two features that can help distinguish them from the variety of non-venomous snakes discussed below.
For one, both species have relatively similar patterns. Copperheads have a color and pattern that has been described as Hershey Kisses in chocolate milk, although there is some variation (some appear almost orange) and in the western portion of their range the Hershey Kisses get broad and lose their characteristic shape.
Cottonmouths have a similar pattern, but it’s messier. The kisses aren’t well-defined and there are likely to be spots and blobs all over. Here’s an interesting bit: when cottonmouths and copperheads are babies they look very similar; the pattern is very distinct and striking and they both have yellow or green tail tips.
Over time, cottonmouths lose their distinct pattern and usually become uniformly dark snakes by the time they’re big adults. On the other hand, copperheads keep their patterning throughout their life. Another way to tell the difference between these species is to look for a dark bar running through the eye: cottonmouths have it, copperheads don’t.
If you’re still wondering whether the snake you’re looking at is a cottonmouth or a copperhead, you can check whether you are within the geographic range of either species.
For example, cottonmouths range throughout much of the southeastern United States west to central Texas and north to southern Illinois. If you live somewhere else, like New England, the snake you saw probably wasn’t a cottonmouth (no matter how much your neighbor insists there are lots of moccasins around).
Copperheads, on the other hand, range throughout much of the eastern and central United States (but not extremes, like Maine and the Florida peninsula) west to Texas and a bit of northern Mexico.
There are a few common species that are frequently mistaken for either copperheads or cottonmouths, but before we get into how to distinguish them, a word of advice.
Snakes With Triangular or Diamond-Shaped Heads – A Complete Guide
The triangular or diamond-shaped head is a distinctive feature seen in many species of snakes. This unique head shape is the result of evolutionary adaptations related to the snake’s way of life. In this comprehensive guide, we will explore the reasons behind the triangular head, look at some examples of snakes with this trait, and learn identification tips.
What Causes the Triangular Head Shape in Snakes?
There are two main reasons snakes have developed the triangular head shape:
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Venom Glands – In venomous species like vipers and cobras, the venom glands are located towards the back of the head. These enlarged glands give the head a wider, triangular appearance. The associated muscles and ducts for injecting venom may also contribute to the distinctive shape.
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Muscles – Powerful muscles attach to the sides and top of the skull in snakes that kill prey by constriction, such as boas and pythons. These strong muscles give the head a broader, more triangular look compared to the neck.
In both cases, the triangular shape allows for a larger head and greater strength to subdue and overpower prey. Non-venomous species also use this shape to mimic venomous snakes and deter potential predators.
Are All Snakes With Triangular Heads Venomous?
While many venomous snakes do have distinctly triangular heads, not all triangular headed snakes are venomous. Some non-venomous species like pythons and rat snakes have naturally wide, triangular skulls Other colubrid snakes like water snakes or garter snakes may flatten their heads defensively to appear more threatening.
Therefore, head shape alone is not a foolproof way to identify a snake as venomous Misidentification based solely on head shape has led to people killing harmless snakes or being bitten by assumed non-venomous species It’s best to learn other identification features besides the triangular head.
Examples of Venomous Snakes With Triangular Heads
Let’s look at some specific examples of venomous snakes possessing the iconic triangular head:
Rattlesnakes – All rattlesnake species have a pronounced triangular head that houses their heat-sensing pits and large venom glands. This includes prairie rattlesnakes, timber rattlesnakes, sidewinders, and diamondback rattlesnakes. Their triangular head supports their hinged hollow fangs.
Copperheads – Copperhead species like the broad-banded copperhead and northern copperhead are easily identified by their flat triangular head which is distinct from the narrower neck. The copperhead’s venom glands give it this distinct hammerhead look.
Cottonmouths – Also called water moccasins, cottonmouths have thick muscular bodies and wide triangular heads adapted for their aquatic ambush hunting. Their triangular head holds large venom glands.
Coral Snakes – An exception to the vipers, coral snakes have a deadly neurotoxic venom but a rounded head more like cobras. The vibrant red, yellow and black banding distinguishes coral snakes.
Examples of Non-Venomous Snakes With Triangular Heads
While non-venomous snakes lack venom glands, some have naturally wide triangular skulls or defensively flatten their head to appear more threatening. Examples include:
Pythons and boas – As constrictors, pythons and boas have strong jaw muscles attached to the sides of the triangular skull. This gives them a broader head and allows them to subdue large prey.
Rat snakes – An adept climber, the rat snake has a triangular head for its hunting lifestyle. But it kills prey through constriction rather than venom.
Garter snakes – Though small, garter snakes belong to the genus Thamnophis, members of which can flatten their head defensively causing a triangular look.
Water snakes – Water snakes flatten out their neck to seem more imposing. This gives their head a wider triangular shape compared to the body.
Identifying Venomous Triangular Heads
When encountering an unknown snake, look for these clues besides the triangular head to determine if it is venomous:
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Cat-like vertical pupils – Venomous pit vipers often have slit-like pupils while non-venomous snakes have round pupils. Coral snakes are an exception.
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Heat-sensing pits – Venomous vipers have distinctive heat-sensing pits between eye and nostril.
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Diamond, checkerboard patterns – Venomous rattlesnakes and copperheads feature these marking patterns.
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Rattle on the tail – All rattlesnakes have a segmented rattle, though some may lose it over time.
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Aquatic habitat – Cottonmouths and other venomous water snakes are found near water.
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Red touching black bands – Coral snakes have red and black bands touching, while similarly patterned kingsnakes have red touching yellow.
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Defensive posture – Venomous snakes may hold their ground while non-venomous snakes tend to flee.
What to Do if You Encounter a Snake
If you come across any unknown snake, keep a safe distance since snakes can strike up to half their body length. Do not handle or disturb the snake. Try to note features like head shape, markings, pupils, habitat etc. If possible, take a photo and consult an expert to identify if it is venomous. Whether the snake is venomous or not, it’s best to leave wild snakes alone and give them space. Educating yourself about local species is key to staying safe while respecting these fascinating reptiles.
Beware the Rules of Thumb
You’ve already learned the ground rules to avoid misidentifying animals in a previous Cool Green Science blog, and they all apply here too. But snakes add a layer of complexity: venom. There are tons of tips out there (and in here) to help you distinguish venomous snakes from those that are harmless; not all of them are particularly helpful.
For example, many people will tell you that pit vipers (like cottonmouths and copperheads) have a triangular or diamond-shaped head. But, this is relative; you need to have looked at a lot of snake heads to know which are relatively triangular and which are not.
Also, lots of non-venomous snakes flatten out their body and neck when they are feeling unsafe, this makes their heads look very triangular!
If you really want to learn how to identify snakes, I recommend getting a copy of Peterson’s Field Guide to Amphibians and Reptiles and go through the process of trying to identify every snake you find (you can do this for pictures you find online too). Note that there is a separate version for the western United States.
Over time, you will start to get a feel for the different species. I also suggest that anyone interested in learning how to recognize snakes join the Snake Identification Facebook group and watch snakes get identified in real-time. It won’t be long before you start identifying them too.
Okay, with these caveats aside, let’s start with the copperheads, which are often confused for a wide variety of species.
Copperhead or Common Watersnake?
At first glance, common watersnakes (Nerodia sipedon) look like they have a similar pattern to copperheads, but look closer. The Hershey Kisses are upside down.
These shapes look more like saddles. As you might expect from their name, watersnakes spend a lot of their time in the water; copperheads rarely do.
So, if you see a snake swimming around or even submerged, remember that this is snake is more likely to be a watersnake than a copperhead.
Snake with Triangle Shaped Head – Venomous? The Diamondbacked Water Snake
FAQ
Are triangular heads snakes poisonous?
Many people believe that all snakes with triangular-shaped heads are potentially venomous. Although all pit vipers (rattlesnakes, copperheads, cottonmouths) in the eastern United States have broad triangular heads, so do some non-venomous species such as water snakes (Nerodia).
Is a diamond head snake poisonous?
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Diamondback snakes, like rattlesnakes, are part of the vipers family, which are known for being venomous.
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Venomous Bite:They have a potent hemotoxin venom that can cause tissue damage and is painful to humans.
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Rattlesnake Identification:Rattlesnakes are easily identified by their triangular or diamond-shaped head and the rattle on their tail.
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The eastern and western diamondback rattlesnakes are two of the most iconic and recognizable venomous snakes in North America.
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Avoidance:It’s important to note that rattlesnakes are not aggressive and typically avoid confrontation, but it’s best to avoid them and not intentionally disturb them.
What does it mean if a snake has a diamond-shaped head?
harmless snakes have roundheads. and venomous snakes have triangle. or arrowhead or diamond shaped heads. In North America, the most common cause of snake bites are pit vipers. So your rattlesnakes, your pygmy rattlesnakes, your copperheads and cottonmouths, these have large venom glands on the top of their head.
Do copperheads have diamond heads?
Copperheads have diamond-shaped heads and cat-like eyes. These two characteristics are not as easy to spot as the snake’s patterned skin so it can make identifying much harder. Young copperheads sport a bright green tail and are the easiest to differentiate between other types of snakes.