Are Reptiles Poisonous? (9 Poisonous Snakes and 5 Lizards)

At least 100,000 people globally die from snake bites every year. While we know that snakes are venomous, can that be said of every reptile? Specifically, are all reptiles poisonous?

Not all reptiles are poisonous. Snakes like the Arizona Black Rattlesnake, Coral snake, and diamondback are extremely poisonous. However, snakes like milk snakes and rattlesnakes have zero venoms. Also, most lizards are non-poisonous except the likes of Gila monster and the Komodo dragon. Other reptiles like turtles and chameleons are totally non-poisonous.

There is so much to know about the toxicity of reptiles. Why, in the first place, are reptiles poisonous? Which snakes and lizards are the most toxic? Also, how can you tell if a lizard is poisonous?

These and many more questions we will vastly answer in this guide.

Why Reptiles are Poisonous?

Venoms are toxins naturally secreted by animals. Commonly, such toxins are deployed for survival. This survival can be in self-defense or preying on other animals.

The specific application of venoms varies across reptiles. Take snakes, for example.

They leverage their venom to defend themselves against bigger predators and hunting preys.

How Many Reptiles are Poisonous?

There is a varying level of venomousness across reptiles. Snakes tend to have the most potent venoms among reptiles. 

Some of the most venomous snakes today include the Arizona Black Rattlesnake, coral snakes, and the Arizona diamondback.

But not all snakes have fatal venoms. There are other mildly venomous snakes like Night Snake, Lyre Snake, and Black-headed Snake.

Species like the milk snake and the rattlesnake can’t kill if they bite you.

The same variation applies to lizards. The Mexican beaded lizard, Gila Monster, and Komodo dragon easily rank among the lizards with the highest venom content.

However, for these lizards, these their venom glands are not developed to kill humans. That said, they could be fatal for much smaller animals.

Top 9 Poisonous Snakes

Inland Taipan

The Inland taipan is hands-down one of the world’s most venomous snakes. Just a drop of this snake’s venom could mean death for the victim.

This snake’s venom is infused with an enzyme that aggressively facilitates the victim’s body sucking in the toxins. This leads to death much faster.

King Cobra

The King Cobra is the longest among all poisonous snakes in the world. Typically, this snake reaches 18 feet in length.

The King cobra rarely bites once. It tends to bite a victim at least three times rapidly. But just a bite from the King cobra can deliver as much as 7mm of venom into the victim.

It is not uncommon for that bite to kill a human victim within 15 minutes. For context, a King cobra bite can kill a grown elephant within hours.

Saw-scaled Viper

It is easy to tell the saw-scaled viper from its characteristic hissing sound. The venom from this snake is dangerous, notorious for obstructing blood clots.

Commonly, victims bitten by a saw-scaled viper experience internal bleeding. This can culminate in kidney failure.

In less severe cases, the bite site can swell with acute pains felt around the region.

Black Mamba

This is by far the most venomous snake in Africa. For context, the black mamba can kill a fully grown man with barely two venom drops.

This venom triggers muscular paralysis. Once administered into the victim’s bloodstream, the black mamba’s toxin attacks the critical connections between muscles and nerves.

More than paralysis, victims, in worse cases, suffer fatal heart attacks.


A venom from the boomslang is almost guaranteed to offset bleeding – both outside and inside.

Patients bitten by boomslangs experience severe muscle hemorrhages. There are also cases where victims suffer bleeding in the brain.

Extensive dissemination of the venom in the patient’s bloodstream would result in blood seeping out of the nose and gums or through urine and saliva.

It is not uncommon to see victims vomiting to death.

Russell’s Viper

This is one of the most poisonous snakes in South Asia. Zooming into the numbers, more than 55,000 people in India die from snake bites annually, with Russel’s Viper accounting for a large slice of such deaths.

The Russel viper’s venom is so dangerous victims end up with acute internal bleeding, kidney failure, and several organs damaged.

Eastern Tiger Snake

This is a beautiful gangster. Decorated with bands of black and yellow, the Eastern Tiger snake’s dazzling looks easily masks the lethality of its venom.

A bite from the Eastern Tigers can poison a grown man within 17 minutes. A significant number of deaths are attributed to this snake every year.


The Fer-de-lance is admittedly not a celebrity among snakes. But it is not any less dangerous.

Upon injecting its venom into a victim, the victim quickly experiences significant skin darkening as their body functionalities begin to fail, ending in death.

The Fer-de-lance’s venom blocks the body’s capacity to clot, commonly leading to unrestrained bleeding.

Banded Krait

The Banded Krait is closely related to the cobra. It is predominantly resident in South China.

A bite from the banded krait can deliver 20–114 mg of venom to the victim. This leads to diarrhea, severe stomach aches, and vomiting.

Victims can die from suffocation when the vomiting is not curtailed early enough.

Top 5 Poisonous Lizards 

While not as venomous as snakes, Lizards are poisonous within their rights. Here are five of the most toxic lizards alive.

Gila Monster

The Gila monster retains the inglorious title of being the most poisonous lizard alive.

When injecting its venom into a victim, the Gila monster chews on the site tightly, attempting to penetrate its victim’s flesh.

This lizard has jagged teeth with reasonable sharpness. This helps it grip the skin and puncture it.

Upon such penetration, the venom is administered via the Gila monster’s glands into the cut opening in the victim’s skin.

Lace Monitor

The Lace Monitor has a fairly venomous bite. While barely severe on its own, the lace monitor’s venom could cause infections if not promptly attended to.

A consolidation of the lace monitor’s venom in the patient’s bloodstream could hinder blood clotting for hours, with the victim often feeling shooting pain.

The Komodo Dragon

The Komodo dragon is one of the biggest lizards in existence. It also features among the most poisonous.

The Komodo dragon’s venom contains toxic proteins. Typical of hemotoxic venom, this lizard’s bite can trigger muscle paralysis.

Disruptions in blood clotting often accompany such paralysis.

Beaded Lizard

The Beaded Lizard shared a strong biological connection with Gila monsters.

While they characteristically feed on flesh, the beaded lizard has competent (compared to Gila monsters) venom glands.


Iguanas don’t have the most sophisticated venom glands. In particular, iguanas’ venom glands are atrophied, meaning their fatality is almost zero.

The bite can prick you or even cut you in some cases, but its venom is almost harmless. This makes them common acquisitions among collectors of exotic pets.

How Do You Know if a Lizard is Poisonous?

Sadly, unless you are an avid lizard connoisseur, you can’t tell a poisonous lizard until it has bitten you.

A lizard’s toxicity is typically discerned from the symptoms that escort its bite. Bites from the most venomous lizards can cause localized swelling, shooting pain, and disrupted blood clots.

In some cases, you may feel strangely weak, nauseous, or even unusually light-headed. It is not also out of place to notice increased sweating and burdened breathing.

You Might Also Like:

About The Author

Scroll to Top