Which Lizards Are Venomous?

Are you wondering which lizards are venomous? Everyone knows that there are many species of venomous snakes in the world – rattlers, black mambas, and cobras being probably the most well-known. But did you know that there are actually two species of venomous lizards too?

Venomous Lizard #1 – Gila Monster (Heloderma suspectum)

Gila monsters are native to the southwestern deserts of the U.S. and northwestern Mexico. They are the largest land-dwelling lizard in the U.S. and can reach lengths of up to two feet and weigh over five pounds. They are black with orange, red, or pinkish-colored patches.

Because they are considered a threatened species (not to mention are dangerous animals!) it’s not always legal to keep a gila monster as a pet. It varies depending on where you live.

Which lizards are venomous?

The venom of a gila monster is a fairly mild neurotoxin. The lizard does not possess fangs but does have sharp, serrated teeth. This means that in order to inject its venom, the monster will bite, hang on, and chew to allow the wound to open up and the venom to flow into the bloodstream. In other words, their teeth do not “inject” venom. Ultimately, because it bites like a bulldog, the bite will be very painful and could cause temporary paralysis or difficulty breathing, but is generally not fatal if treated properly.

By nature, Gilas are burrowers and in captivity, they behave much the same as they would in the wild. They spend most of their lives under ground and will eat voraciously, so if you are keeping gila monsters, you should probably be an experienced herp hobbyist who knows the habits of these lizards.

Venomous Lizard #2 – Beaded Lizard (Heloderma horridum)

The Beaded Lizard is a close relative to the Gila Monster with similar body shape, venom delivery methods, and even skin texture. The Beaded Lizard gets larger than the Gila Monster though and can max out at three feet long and weigh as much as 45% more than its lizard cousin. Beaded lizards are also typically duller in color with browner bodies and white or yellowish splotches.

mexican beaded lizard eating
The resident Backwater Reptiles beaded lizard swallowing a pinkie.

Because the Beaded Lizard and Gila Monster both primarily consume eggs, scientists are not 100% sure as to why these lizards are venomous. Interestingly enough though, the Beaded Lizard’s venom has been discovered to contain enzymes that are useful in the treatment of diabetes.

Fun fact: the Beaded lizard can consume around 30% of its body weight in one feeding! We feed ours thawed fuzzy mice, around six per feeding, and the lizard is barely a foot long.

beaded lizard venomous - heloderma horridum

Beaded lizards (and gila monsters) use their tongues much like snakes do to taste and smell the air. They possess Jacobson’s organs which filter the sensory data obtained by their tongues so that it can be transmitted to their brains for interpretation.

The venom of the Beaded Lizard causes respiratory paralysis and failure, but is rarely fatal to humans.

Honorable Mention #1 – The Komodo Dragon (Varanus komodoensis)

Komodos are extremely large lizards and therefore eat large prey animals such as deer, wild pigs, and even water buffalo. Sometimes the Komodo Dragon doesn’t manage to kill its prey in a single sitting, but the dragon is a patient lizard and will wait until it’s venom has worked its magic, which depending on the size of the animal, could take a day or two.

Venom researcher Bryan Fry discovered that the Komodo’s venom is delivered via chewing, much like the Beaded Lizard and Gila Monster’s venom. Once the venom has entered the blood stream, it can cause rapid decrease in blood pressure, expedite blood loss, and send a bitten animal into shock, making the prey animal too weak to escape or fight back.

Honorable Mention #2 – Monitor Lizard Family & Iguana Family

New scientific research suggests that monitor lizards and lizards in the iguana family also possess venom glands. Not to worry though – your pet iguana or pet Savannah monitor is not dangerous to you through its bite. The trace amounts of venom produced in these lizards is only strong enough to take down small prey items such as mice or birds. It is not harmful to people.

This is still a somewhat controversial topic of discussion and we’re awaiting further scientific data and studies until we officially proclaim monitors and iguanas venomous for the purposes of this blog.

Beaded Lizard Care (Heloderma horridum)

We have put together a Beaded lizard care sheet based upon our experiences with this amazing species. There are only two species of lizards in the whole world that can be classified as truly venomous – the Mexican Beaded Lizard (Heloderma horridum) and its close relative the Gila Monster (Heloderma suspectum). This blog entry will focus on the Beaded Lizard and how to safely keep this lizard in captivity.

beaded lizard care
The resident Backwater Reptiles beaded lizard swallowing a pinkie. Our care sheet will cover foods, caging, etc.

First of all, the Beaded Lizard is not a pet to be handled like most lizards. Although their venom causes paralysis, difficulty in breathing, and seizures, a beaded lizard bite is rarely fatal in humans. However, because many people don’t know if they could have an allergic reaction in addition to the effects of the venom, Backwater Reptiles does not recommend taking these lizards out of their enclosure unless absolutely necessary (i.e. to clean the cage).

It’s also useful to understand that the Beaded Lizard has a “bulldog” mentality when it comes to jaw strength and power. Although they might seem docile at first, if one of these guys bites you, it will hold on with tenacity and give the venom time to get into the wound it creates with its sharp teeth. Their strikes are very, very quick.

Our baby Beaded Lizards eat voraciously and can consume as many as four fuzzies or pinkies in a single sitting. It’s said that they can consume close to one-third their body weight in one meal.

Luckily, like most snakes, beaded lizards will do fine eating every few days and do not need to be fed four pinkies/fuzzies on  daily basis. Although they’re used to desert climates, these lizards do still need a supply of fresh water available to them at all times.

Beaded Lizards don’t need a very large enclosure to do well. Just be sure they have a proper basking area as well as a place to hide as they are usually fairly secretive animals.

Again, Backwater Reptiles does not recommend handling your beaded lizard, but when you must remove the lizard from its cage to clean it, we recommend wearing very thick leather gloves that reach up to the elbow. Breeders have also been known to offer the lizard a pinkie or fuzzy mouse on a pair of tongs. The lizard will bite the food and hold on tight and then the lizard can be carefully transported to a separate holding container while it is hanging onto the tongs/food without actually having to touch the lizard.

heloderma horridum care
Beaded lizard care is quite straightforward–they are undemanding animals that reach a large size.

While keeping a Beaded Lizard can certainly be a very rewarding experience, these lizards are most definitely best for experienced herpers, and cannot be shipped through standard channels (airport-to-airport only).

Backwater Reptiles is thinking about offering these beautiful lizards for sale. How many of you would be interested in owning one? Let us know in the comments and maybe we’ll start keeping some in stock! :)