10 Biggest Lizards in the World

If you like lizards, you’ve come to the right place because I also like lizards. So, today, we’ll like lizards together and dive into the world of the biggest species on earth.

The goal is to showcase the immense variety you can find in the reptile kingdom and highlight why lizards qualify as some of the most fascinating animals in the world.

Here are 10 of the biggest, meanest, and most unique lizards on the planet:

1. Komodo Dragon

komodo dragon

Komodo dragons are probably the most vicious lizards on the face of the earth. These cruel and demonic predators can reach sizes of up to 10 feet and weigh in excess of 350 pounds.

They possess thick and powerful bodies with massive claws, extremely powerful jaws, and an envenomed bite that can deliver neurotoxic effects.

The dragon’s mouth is literally a deadly weapon, not only due to the jaw power and steel-like neck muscles but the potent venom and bacterial cocktail as well. Komodo dragons were previously thought to possess the so-called dirty mouth bite.

The idea was that the effects of the dragon’s bite were due to the myriad of bacteria inhabiting the dragon’s mouth and causing immediate infections and rapid and painful death.

That’s only half the truth, as Komodo dragons also possess a venom cocktail that delivers a mix of neurotoxic and hemotoxic effects. The powerful and serrated teeth inflict gruesome wounds, as the venom causes paralysis, hemorrhage, blood clots, and tissue destruction.

The reptile’s bite can kill a human in hours.

Interesting Facts:

  • Komodo dragons are ambush predators because they prefer to move slowly to conserve energy. However, they can reach speeds of up to 13 mph in short bursts
  • Komodo dragons can also swim for short periods, which they only do when chasing prey or evading predators
  • Adult Komodos have no natural predators, but juveniles are preyed upon by adult Komodo dragons, feral dogs, civet cats, birds, snakes, etc.
  • Komodo dragons are some of the most vicious predators on earth, as they prefer to consume their prey alive

2. Black Dragon (Water Monitor)

Water monitors make for an interesting reptile species that are somewhat similar to Komodo dragons in appearance.

These are large and powerful reptiles, capable of growing up to 7-8 feet, although many specimens, especially females, won’t exceed 5-6 feet. These reptiles have long, bulky, and powerful bodies with very long necks and sharp heads.

They’re quite recognizable in their natural habitat thanks to their distinct spotted color pattern.

Unlike the Komodo, these lizards are not venomous. However, they do possess powerful jaws and neck muscles, along with sharp and curved talons they use for holding and dismembering prey.

As opportunistic feeders, black dragons can consume anything that contains protein, including fish, small mammals, other reptiles, birds, and even eggs.

They spend most of their time near bodies of water that provide them with ample hunting opportunities.

Interesting Facts:

  • Unlike the Komodo, this lizard does quite fine in captivity, provided you ensure optimal living parameters
  • Water monitor lizards are peaceful and won’t attack humans, generally speaking. This qualifies them as great pets, especially when raised in captivity
  • These reptiles can live up to 20-or-more years in the wild
  • Water monitor lizards now showcase several morphs thanks to successful selective breeding, which was previously considered impossible

3. Crocodile Monitor

Despite what the name says, this is not a crocodile. Instead, it is a massive lizard, capable of growing up to 8 feet and weighing up to 50 pounds.

They are quite intimidating at first sight, thanks to their nimble bodies and thick heads with well-defined characteristics, and they should be. These animals are fierce and intelligent predators that exhibit violent behavior.

They have long and powerful necks, sharp claws, and serrated teeth capable of inflicting serious wounds. More impressively, these lizards are basically arboreal but also exhibit aquatic behavior, the last of which is responsible for their name. These reptiles rank as carnivorous scavengers, as they feed on both live and dead prey, depending on what they can find.

The typical crocodile monitor comes in dark colors, usually black with yellow spots covering the entire body.

The animal’s skin is folded around the neck, which is typical for big lizards.

Interesting Facts:

  • The crocodile monitor only lives up to 15 years in the wild
  • Some tribes view these lizards as evil spirits that eat humans and spit fire, so they hunt and skin them alive
  • The crocodile monitor has an unusual hunting tactic. Instead of chasing or ambushing the prey, the lizard calculates the direction of the prey’s movement and circles around to meet the animal on its path
  • Crocodile monitors are not fit as pets, no matter what you may read elsewhere; they require specialized care, are very pretentious, and extremely aggressive

4. Blue Iguana

There’s no doubt that blue iguanas are some of the most exciting reptiles on earth. They are the closest you’ll get to the idea of an exotic pet.

Most specimens showcase an intense blue coloring with different color variations, depending on the lizard. But it’s the reptile’s overall look that spikes its value.

Blue iguanas can grow up to 5-6 feet and weigh up to 25 pounds as adults. They have thick, compact, and powerful bodies with short but muscular legs.

All blue iguanas possess neck pouches covered by bumpy skin and flanked by skin flaps down the neck. The lizard also has extremely powerful and long tails and a raw of serrated growths covering the entire back, head to tail.

The lizard’s appearance reminds of a prehistoric dragon, which is why this species is so valuable among breeders.

Blue iguanas are herbivorous animals that can live up to 20-30 years in the wild and around 15 or more years in captivity.

They’re not exactly widespread in captivity, though, due to their advanced care requirements.

Interesting Facts:

  • Blue iguanas are difficult to socialize with but can be quite friendly and docile once befriended
  • Despite their difficulty of care, blue iguanas rank as some of the most commonly kept lizards in the reptile trade
  • These iguanas tend to sneeze a lot, which is their way of eliminating excess salt from their bodies
  • Blue iguanas are known to be good climbers that prefer to spend their days basking in the sun

5. Savannah Monitor

The savannah monitor qualifies as a great African hunter with sharp teeth, ominous claws, and a powerful body. These are medium-sized lizards with distinct characteristics like powerful bodies, fat bellies, and short and compact heads.

There isn’t much variation in terms of coloring here, as most specimens come with an earthy look. The most predominant colors are earth-yellow, brown, and grey, often with subtle spotted patterns.

These opportunistic hunters demand a high-protein diet, which they acquire via hunting and scavenging. Their preferred meals include mammals, reptiles, birds, eggs, and animal carcasses, no matter the degree of decomposition.

These lizards are not venomous, so they use their physical strength, teeth, and claws to procure their meals.

Interesting Facts:

  • These lizards are quite popular as pets, despite their size and controversial legal status
  • Savannah monitors can live up to 20 years in the wild but only half that in captivity
  • These reptiles use their powerful tails as defensive tools and can inflate their bodies to intimidate predators
  • Savannah monitors are some of the friendlier and more docile lizards, which explains their popularity as pets

6. Green Iguana

Green iguanas are by far the most popular pet lizard you can find. These reptiles are endemic to the tropical forests of Central and South America, where they inhabit various ecosystems. These include lush forests with plenty of vegetation that the lizards can use for predator evasion and hunting.

Green iguanas rank among the largest pet reptiles in the world, capable of reaching up to 6 feet, sometimes even more. This is especially impressive if you consider that this species is herbivorous and consumes mainly leaves, flowers, fruits, etc.

They also require calcium and vitamin D supplementation to prevent calcium deficiency and Metabolic Bone Disease, which are prevalent among reptiles.

The green iguana is also one of the most handsome lizards you can buy. Although it may not sound like it, this species comes in various shades of green and may even exhibit different patterns.

These iguanas have a dorsal crest, and trademark skin folds under the chin. The lizard’s long fingers with sharp claws allow it to climb trees with relative ease. Most green iguanas have long and powerful tails with a banded pattern.

Interesting Facts:

  • Green iguanas are typically docile and friendly but can bite and scratch if threatened
  • The largest green iguana males can reach 6.5 feet in length and weigh approximately 20 pounds
  • When startled, wild iguanas can jump from impressive heights into the water stream beneath them and swim away to evade the danger
  • A wounded iguana is more dangerous due to it being more vulnerable

7. Spinytail Iguana

The spinytail iguana is an awkward one because it looks like a mix between an iguana and a Komodo. This rock lizard qualifies as a medium-sized reptile, capable of reaching up to 18-20 inches as a full-grown adult. The lizard has a distinct appearance, albeit not as colorful as other species.

While the spinytail iguana has adapted to a variety of habitats, it prefers rocky ecosystems with some vegetation, if possible.

This explains the lizard’s dull coloring with colors like black, grey, and various nuances of brown. Some specimens have a banded pattern with vertical bands covering the lower half of the body.

Males also have a sharp dorsal crest along the spine, which they can flare up when threatened.

Interesting Facts:

  • Spinytail iguanas are incredibly fast and agile for their size, so it’s common for them to escape their enclosure if these are not secure
  • Males are particularly territorial, so you should never pair 2 or more in the same enclosure
  • Spinytail iguanas have a compact body with a short neck – a body conformation perfectly adapted to their harsh ecosystem
  • Spinytail iguanas can blend in their environment thanks to their innocuous coloration

8. Marine Iguana

I bet you didn’t expect to read about an aquatic iguana today, yet, here you are. This is probably one of the most fascinating species you can find in the wild.

The lizard can reach 4.5 feet and weigh approximately 20 pounds or more, depending on the specimen. But it’s the reptile’s appearance that elevates this species to its unique status.

Marine iguanas look exactly like Godzilla in terms of body shape, physiognomy (facial features), and behavior. The body is solid and compact, with powerful and thick legs and an even thicker neck.

The lizard’s head is short compared to land iguanas, and the animal displays thick lips and bumpy skin on the forehead. The reptile’s coloring matches the environmental requirements.

Most specimens come in a combination of red, brown, black, yellow, and even blue in various intensities and patterns.

The dorsal crest of sharp spines gives the animal personality and character.

Interesting Facts:

  • Marine iguanas are not suitable for life in captivity because they are protected under the law; they’re also known to die in captive conditions, no matter the level of care
  • Marine iguanas can remain submerged for up to an hour and dive as deep as 33 feet
  • These iguanas have a variety of natural predators, including hawks, snakes, feral cats, and aquatic creatures like sea lions and fur seals
  • Marine iguanas feed primarily on red, green, and brown marine algae, which are only present in intertidal oceanic zones; this specialized diet makes iguanas unfit for a captive lifestyle

9. Argentine Black and White Tegu

This is a strange but beautiful American lizard, which you can find primarily in areas like Argentina, Uruguay, and Brazil.

This adaptable lizard can thrive in a variety of ecosystems like rainforests, savannas, and desertic regions, so long as they have access to food, shade, and water.

The lizard’s appearance makes up for at least 50% of its charm. These lizards only come in 2 dominant colors, black and white. The pattern may vary drastically between the different specimens, but it mostly comes down to spots. The underbelly contains more white, while the dorsal area contains more black.

Males and females are similar in appearance, but males appear bulkier and stronger and have neck pouches that they can inflate to increase their head size. This is likely a dominant behavior because tegu males don’t have time to play games with one another. If you know what I mean.

Interesting Facts:

  • If you’re interested in acquiring an Argentine Black and White Tegu, prepare to pay between $250 and $500 for a specimen, depending on its age, size, and characteristics
  • These lizards can live up to 15-20 or more in captivity and up to 12 years in the wild
  • These are intelligent reptiles that you can tame and turn them friendlier and more docile
  • Argentine tegus have a knack for exploration and climbing; they are active diggers and proficient escape artists, which is why you need to secure their enclosure to keep them in

10. Gila Monster

The Gila monster is well-deserving of its ominous name. You can tell that the reptile isn’t exactly the friendliest animal you can meet in the wild, which is especially obvious thanks to its coloration.

Gila monsters display a 2-color pattern, usually containing yellow and brown. The face is always black, no matter the body’s coloration. The tail is thicker than any other lizard species you may have seen.

Some specimens replace yellow with red for an even flashier look. The reptile’s coloration is a warning sign to potential predators to keep their distance. If that doesn’t work, the lizard’s venomous bite will.

This reptile has a venom delivery system similar to that of the Komodo dragon. The venom covers the animal’s lower teeth and enters the wound upon bite.

The neurotoxic cocktail causes pain, localized swelling, and paralysis, and it’s known to kill humans in more severe cases. Medical assistance is vital when dealing with a Gila bite.

Interesting Facts:

  • Gila monsters are unsuitable for captivity due to their venomous bite and protected status
  • Gila monsters are carnivorous scavengers that can consume anything, including mammals, reptiles, birds, eggs, and carcasses
  • Gila monsters can extract all of the nutrients they need for a year in just 3-4 large meals and can survive months without food

These lizards are some of the slowest reptiles, only reaching maximum speeds of up to 1.5 mph


These are some of the world’s largest and most fascinating lizards, each with unique characteristics and behaviors.

As you can see, they’re not all fit for captivity, so choose wisely. As for the rest, you need to visit their natural habitat to witness them in their full glory.

Just make sure it’s not a Komodo or a Gila monster. You don’t want to witness these beasts in their full glory at all.

Robert from ReptileJam

Hey, I'm Robert, and I have a true passion for reptiles that began when I was just 10 years old. My parents bought me my first pet snake as a birthday present, which sparked my interest in learning more about them. read more...