Do All Non-Venomous Snakes Have Round Pupils?

Do All Non-Venomous Snakes Have Round Pupils?

Wondering what are the physical characteristics of a venomous snake? How could you tell the difference between a venomous and non venomous snake species that look alike? Is it true that all the non-venomous snakes have round pupils?

I am author Pourandokht Mazaheri, a passionate snake enthusiast and a member of the academic research center concerned with the study of snakes. I am also a writer for the Snake Store Team of herpetologists. Today, I have decided to share the information on the identification between venomous and non-venomous snake species information. A knowledge that could be a matter of life and death for those interested in wild snakes, or those in constant contact with natural snake habitats. 

Round pupils are a sign of the non-venomous nature of the snakes. Although this is a general rule and does not include particular species such as the venomous American coral snakes. General call on a snake’s Toxicology must be made after examining other physical features and behavioral patterns.

This article covers the following contexts:

  • A definitive overview on the venomous snake

  • General and physical characteristics of non venomous snake species

  • The difference between the eye pupils of non-venomous and nocturnal venomous species

Curious about snakes, let's find out who to recognize a non venomous specie from a venomous variety.


1- What Are Non-Venomous Snakes?

Non-venomous snakes are usually differentiated from venomous snakes on the basis of whether their bites contain venom or not. However, the word 'non-venomous' is often confused with the term 'not poisonous'. The two words have completely different meanings. Let’s see that now.

Rattlesnake with open mouth and fangs

a) Non-venomous or not poisonous?

In the large family of snakes, there are indeed serpents with various characteristics. A poisonous animal transfers its toxins into your body when you consume it. On the other hand, venomous animals transfer their venom into your system when they intentionally try to bite or sting you.

Snakes that are venomous have glands in their mouths that produce venom and cause highly undesirable effects on their victims when they are bitten. Therefore, non-venomous snakes do not have any venom in their bites.

b) How can you tell if a snake is non-venomous or not?

There is no definite feature that sets apart venomous snakes and non-venomous snakes. For example, some experts choose to identify these two types by color. They believe that venomous snakes have more sharply colored scales than non-venomous serpents. This can be difficult to prove as the Coral Snake, and the Scarlet Kingsnake both have almost the same shades of bands wrapped around their bodies.

Scarlet Kingsnake in the sand in Florida

So, if you are not a trained expert, it is better to stay away from any snake you see that has a brightly colored hide. However, the Scarlet Kingsnakes are non-venomous, but seeing it from a distance might lead one to believe that it is a Coral Snake that is famous for being highly venomous. Incorrect identification of a venomous snake as a non venomous species can be a fatal mistake, which is why it is always advisable to contact professionals if you ever come across the species you are doubtful about.

Another thing you could look for when trying to determine whether a snake is venomous or not is its behavior and habitat. It can be difficult to remember all the individual behaviors of each species, so make sure to only check up on the ones close to your area. Whenever you cross paths with a snake, observe the area surrounding it. Cottonmouth Snakes live near water, while Copperhead Snakes live in wetlands near forests. Both these snakes are venomous, so it is wise to be wary of them and keep at a distance.

When considering the shape of the head of the two types, venomous snakes often have triangular heads that are broad. This shape is meant to be threatening and will usually protect the snake from protectors.

green viper, triangle headed, venomous

An interesting ability that non-venomous snakes possess is the ability to change the shape of their heads in a manner similar to venomous snakes. This means that although non-venomous snakes usually have round or elongated heads, they can flatten them when predators are nearby. This is an important bit of information to remember, as snakes have the ability to sense predators from miles away. So, non-venomous snakes might flatten their heads and make you think they are venomous if you seem threatening to them.

Whether they have venom or not, most snakes have common physical characteristics. However, with the proper knowledge, it is possible to differentiate them. Let's see how these non-venomous crawling reptiles are distinguished.

snake painting canva


2- Non-Venomous Serpents Features

Although the different species of snakes share many characteristics, there are some that are specific to snakes without venom. Let's see the most important of them.

a) Snakes’ teeth

Non-venomous snakes have a different teeth pattern than venomous snakes. When most people think of snakes, they think of fangs. However, fangs are only possessed by venomous snakes. The non-venomous ones have normal rows of teeth, that have a developing process that is very similar to those of humans. When these snakes bite, it is called a 'dry bite', as it does not insert any venom into the victim's body.

Green bush viper in is natural environment with open mouth showing its large venom fangs.

Despite this, some species of non-venomous snakes, such as the Python, can grow up to be several feet long. These species can bring disastrous injuries to their victims, even if they do not have venomous abilities. This is because their bites are still powerful enough to cause major lacerations and wounds. If these wounds are not taken care of, they can turn into infections and cause skin disease or worse. Therefore, non-venomous snakes are just as dangerous as venomous snakes.

b) Snake blood

It is important to remember that, like all reptiles, snakes are cold-blooded. They have immense importance in the ecosystem and they obtain their body heat from their surroundings. Snakes tend to be more active during the day in spring and fall, and more active early morning and evening during the heat of summer. Venomous snakes will usually not bite anyone unprovoked, and they also have a sensory area or pit on the sides of their heads. This is absent in non-venomous snakes and helps to set the two apart from each other.

c) Snake hunting technique

The hunting and preying process for non-venomous snakes is almost similar to those of all snakes. Non-venomous snakes are known to hunt their prey through constriction. The snake will bite its prey once or twice, obviously not transferring any venom, and then wrap itself around the animal entirely. The snake wraps tighter every time the animal exhales, until the animal can eventually, not inhale and dies of exhaustion. This process is relatively quick and it takes under a minute for the animal to die. Simultaneously, a large amount of pressure is applied to the animal's chest and the heart stops beating because there is no room for it to continue beating. In the end, like all snakes, the non-venomous snake also swallows its food whole.

Snake eating a mouse

d) Snake defense

One important feature of non-venomous snakes is that they are very careful of danger and will go to any length to defend themselves. These snakes have the ability to bite their predators, but first, they will try their best at camouflaging and hiding in their surroundings. The snake will attack if it has been left no choice, otherwise, it will gather itself up into a tight ball and keep its head in the center. It may also shake its tail, as rattlesnakes do to produce a noise that will ward off predators. If nothing else works, the snake will attempt to bite the enemy.

So you know a lot more about these beautiful non-venomous animals. Now it's time to look at the most surprising fact about them.


3- Do Non-Venomous Snakes Have Round Pupils?

a) What kind of eyes do non-venomous snakes have?

Non-venomous snakes differ from their venomous counterparts because they usually have round pupils, similar to those of humans. Venomous snakes have vertical pupils, identical to those of cats, that almost look like slits.

Trendy gold snake ring

This feature completely distinguishes non-venomous snakes from venomous ones, but it can not be observed from a safe distance. There is also a large exception to this, as a snake species in the United States, known as the Coral Snake, also has round pupils. This species is very venomous, but it is also easy to identify so there should not be a problem. Along with the round pupils, Coral Snakes also have a blacked nose and colorful bands all along with their bodies.

b) Why do non-venomous snakes have round pupils?

Although most people understand that snakes are dangerous to some extent, they also realize that not all snakes can kill humans. The problem lies in not being able to differentiate between the two. If the eyes of the snakes are considered, it can not be said that all venomous snakes have vertical pupils, or all non-venomous snakes have round pupils. It is important to note that there may also be keyhole-shaped pupils among some species. This proves that the shape of the pupil has almost no connection to whether a snake produces venom or not. It also does not affect the other abilities of the snake. Vertical pupils may also help the snakes with night vision, however, not as much as it does in other animals such as cats.

Green Python eyes

Among the Copperhead species, are the Vipers and Pit Vipers Snakes. These snakes also possess catlike, or vertical pupils. They are the type of snakes that do their hunting through the ambush method. This means that the vipers wait in their hiding spots and wait for their prey to come out, this is when they attack with their venomous bites. Other than this, Vine Snakes are known to have unusual pupil shapes, they are called 'keyhole shaped'. These snakes have a particularly good vision that can be used to see at long distances. In addition to this, Vine snakes do not have fangs like venomous snakes, instead, they have large teeth at the back of their mouths.

For quite some years, scientists thought that having vertical pupils helped snakes to see in the dark. In recent years, however, this theory has been disproved as it has become clear that having vertical pupils in fact helps snakes to move across a horizontal plane. This is due to the fact that snakes usually move on the ground, and also cover large distances. Some powerful venomous snakes are known to have round pupils, including Sea Snakes, which have strong venomous properties. Other venomous snakes are known to have round pupils including taipans and cobras.

4- Vertical serpent eyes: A timeless beauty aesthetic

By building a scientific foundation on venomous snakes’ physical characteristics, you can now easily recognize a poisonous serpent. Additionally, you have learned about the physical characteristics, behavioural patterns and habitat of non-venomous species that helps you further in identification of a snake.

You also are a confidant of a trick that most herpetologists use as the first filter in differentiating between venomous and non-venomous species. If entering the natural habitat of serpents in the wild or having an unexpected serpentine guest in your living environment, you can now save the day by easily assessing the danger levels with your newly gained knowledge.

While numerous snakes have round pupils, vertical serpentine eyes have earned a fame for their hypnotizing allure and exceptional patterns. Human understanding of art and beauty has long been inspired by their magnetic gaze.

Click below and discover the Snake Eye Men’s Ring- epitomizing the perilous beauty in its entirety👇🏼

Snake Ring men's ring

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