What Lizards Are Poisonous (Venomous)?

Are you interested in learning more about different lizard species?

Have you ever wondered what lizards are dangerous and what ones aren’t?

Lizards are fascinating creatures, and some of them make great pets.

If you are looking to learn more about dangerous lizards, you might ask:

What lizards are poisonous or venomous?

There are around 5,000 species of lizards, but in actuality, very few are venomous. These species of venomous lizards are Gila monsters, Mexican beaded lizards, monitor lizards, and some species of iguanas. Venomous lizards are not extremely common, with most being harmless to people, but those who are venomous can do some damage.

For more information on poisonous lizards, keep reading. 

what lizards are poisonous (venomous)

What Lizards Are Poisonous (Venomous)?

Venomous lizards are few and far between, but they do exist. 

Scientists have identified approximately 5,000 species of lizards through their research.

Initially, scientists only identified two kinds of venomous lizards, but they added to the list in recent years. 

Gila Monsters And Mexican Beaded Lizards

Gila monsters and Mexican beaded lizards were the original two venomous lizards.

These two species are closely related, with similar coloring and habitat.

Gila monsters and Mexican beaded lizards make their home in the southwestern parts of the United States and northern Mexico. 

Gila Monsters are black with pinkish-yellow bands along their thick bodies.

They are supported with their short stubby limbs.

Similar in appearance, the Mexican beaded lizard is just slightly larger and a bit darker than the Gila monster. 

Venom glands sit in the lower jaws of these lizards.

When threatened, they will bite and then chew on their prey to make the venom penetrate even deeper into the prey’s system.

These bites are painful, but human deaths are rare, especially if they get medical attention quickly.

Monitor Lizards

Monitor lizards, like the Komodo dragon or Malayan (common) water monitor, have recently been added to the list of venomous lizards.

Originally, experts thoughts the bites from these lizards cause damage due to infectious bacteria passing from the lizard’s mouth to the prey.

Over time, scientists have determined these animals do produce venom and use it for hunting their prey. 

Monitors come in a variety of colors, including tan, green, grey, or brown. 

They have a powerful body with a long neck, sturdy legs with sharp claws, and a very long tail. 

You will find monitors measuring from about 4.5″ inches (11.4 cm) up to about 10′ feet (3.1 m) and weigh

ing anywhere from 2 to 360 pounds.

Komodo dragons are the largest species of the monitors.

Monitors are initially found in Asia and Africa but have come to the Americas, making them an invasive species. 


Iguanas are the least dangerous of the venomous lizards, with some species commonly kept as pets.

As with the monitor lizards, scientists originally thought bacteria was transferred during a bite, rather than actual venom. 

But this has since been debunked. 

Iguanas have a very weak and nearly harmless venom, inflicting more pain with their dozens of sharp and serrated teeth. 

The venom glands sit in both their upper and lower jaws, and when they bite, the iguana can release small amounts of venom.

When you think of iguanas, you probably think of the common green iguana. 

Iguanas have powerful claws, tails, and jaws, and they will use them if provoked.

Some iguanas may reach a size of over 6′ feet (1.8 m) and weigh around 13 pounds.

They also often have a throat pouch and come in many colors, including browns, dark gray, orange, and dull green. 

Bites from iguanas are not very common, but they do happen on occasion. 

When they do, it’s most often to faces, fingers, wrists, and ankles.

A person who is bitten by an iguana is likely to have some severe injuries.

But there are some signs the iguana is ready to bite.

The iguana will stand on all fours and puff themselves up by drawing in a breath.

This is an attempt to look bigger and even more fierce.

They will also lower the dewlap or skin flap found under their chin.

These warning signs are essential to know, but there have been incidences of iguanas attacking without any warning.

For this reason, it is best to avoid these animals if you come across one in the wild. 

Those who keep iguanas do not startle the animal or make it feel threatened, and you will reduce the risk. 

What Are The Symptoms Of Being Bitten By A Venomous Lizard?

Most lizards are harmless to humans, but the ones on this list will cause some damage. 

If you come across one of these venomous lizards, avoid them at all costs, as they will only attack when provoked.

Sometimes things go wrong, and if you or someone you know is bitten, the very first thing to do is call 911 or other emergency services.

This is a priority, as the sooner you get medical attention, the less likely the damage will be severe or long term.

At the site of the bite, you might notice moderate or severe bleeding, accompanied by throbbing or burning pain.

There is likely to be swelling at the wound, and over time the swelling will get worse.

There might also be teeth left in the wound by the animal.

As the poison works its way into a person’s body, the person may feel weak, dizzy, and nauseous.

Vomiting, sweating, and difficulty breathing are also possible.


After reading this article, we hope you have a better understanding of what lizards are poisonous and what may happen if you come into contact with one. 

Bites from venomous lizards are not common, as there are very few venomous lizards.

These bites are serious, and you should seek medical attention when something like this happens. 

These animals are only likely to bite when they feel threatened, so avoiding them is a sure way to reduce the risk.

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