The Largest Lizards in the World

Lizards include over 7,000 identified species. They can usually be seen soaking up some sun during the day, but they prefer hiding under rocks, in trees, or in burrows at night. As part of the Reptilia class, lizards share traits with other reptiles, such as forked tongues and scales. Since lizards are cold-blooded, they prefer hot, dry areas of the world.

Most lizard species lay eggs, but a few give birth to live young. Lizards mature from 18 months to seven years, with some species taking much longer to become fully grown. Some lizards can live over 50 years. They range in size from less than an inch long to over ten feet. Keep reading to find out more about the largest lizard species in the world.

#10: Marine Iguana

One of the most fascinating lizard species is the marine iguana, Amblyrhynchus cristatus. They are the only lizard to swim in the ocean around the Galapagos Islands. The short blunt noses allow them to feed off marine algae and seaweed. When food is scarce, the marine iguana can lose up to 20% of its size. This allows the lizard to survive on less food. Once resources are restored, the lizard will regain its former size. They weigh from 3-26 pounds, depending on which island they inhabit. These lizards average around 4.5 feet in length.

The young marine iguana is generally black. As they mature, their color will change to include red and black, green, red, and grey. They will also become more colorful during the mating season. Female iguanas lay 2-3 eggs in burrows, sand, or volcanic ash. She leaves them to hatch on their own around 95 days later. The lifespan of the marine iguana is around 12 years, but some have been recorded living as long as 60 years.

#9: Galapagos Land Iguana

The Galapagos land iguana, Conolophus subcristatus, is one of just three species of land iguana native to the Galapagos Islands. It will grow to be 28-30 pounds and just shy of five feet long. Their coloration is primarily yellow with white, black, and brown blotches. They are considered vulnerable. The rise in numbers of small animals such as cats, dogs, pigs, and rats has been a cause for the decrease in the land iguana population. More animals are hunting the same food sources, and these animals are predators of the young land iguana and their eggs. 

Land iguanas reach maturity between 8-15 years of age. They can live as long as 60 years. When they mate, the female will search out a suitable nesting spot to bury around 20 eggs. The female will protect her nest against other females looking to use the same nesting area. The males are very territorial and will also defend the nest. The eggs hatch between 85 to 110 days, but it will take about a week for the babies to dig their way out of the nest.

#8: Blue Iguana

As the name suggests, the blue iguana, Cyclura lewisi, is blue to grey-blue. It grows to be approximately 25-31 pounds and is around five feet long. Their coloring helps the iguana camouflage itself among nearby rocks and scrub of Grand Cayman Island. This adaptable lizard makes its home in dry, rocky forests on the coast, semi-deciduous forests, and scrub woodlands. They like to bask in the sun and hide in rocks, crevices, or caves at night. 

This lizard has an average lifespan of 25-40 years. They don’t become sexually mature until they are 4-9 years old. They breed in the spring, typically from April-June. The female iguana can become aggressive and territorial after she mates. She will lay up to 20 eggs which are buried around one foot deep. The eggs generally hatch in 60-90 days. Unfortunately, a high number of eggs succumb to predators. 

#7: Lace Monitor

The appropriately named lace monitor, Varanus varius, is dark gray to black with cream to yellowish lace-like patterns. This is to help camouflage them from their predators. The lace monitor is the second largest lizard in Australia, reaching up to 31 pounds and around 6.5 feet long. They can tell where their predators are by flicking their long, snake-like tongues and tasting molecule remnants. Lace monitors are venomous but not deadly. Their long tails are used for balance while climbing, for whipping as a defense, for swimming, and for dominance when courting the females during the mating season. 

When they lay their eggs, the female monitor will dig the side of a termite mound and lay 6-12 eggs. The termites will rebuild their mound, protecting the eggs from predators and elements. This also keeps the eggs at a constant temperature. After about 8-10 weeks, the female will return to dig out the hatched eggs.

#6: Nile Monitor

Our sixth-largest lizard is the Nile monitor, Varanus niloticus. They have an average weight of 18 pounds, but exceptionally large monitors can weigh as much as 44 pounds. They measure 4-7 feet long. Their tails are nearly 1.5 times the length of their body. They are olive-green to black with cream or yellow V-shaped stripes on their head and neck. These stripes look like bands or spots as you look further down their backs. 

At about two years of age or 14 inches, the females will begin laying eggs. They are deposited in burrows, typically 12-60 eggs at a time, depending on the size of the lizard. The Nile monitor is semi-aquatic but loves to bask in the sun on rocks and tree branches. They are native to Africa and have been seen as high as 6,560 feet above sea level. There have been some Nile monitors spotted in Florida, probably due to escaping or being released from captivity. 

#5: Black-Throated Monitor

The black-throated monitor, Varanus albigularis ionidesi, is native to Africa. They grow to be 60 pounds and up to seven feet long. They are distinguished by their grey-brown scales with yellowish-white markings. The black-throated monitor is often kept as a pet due to their mild temperaments when raised in captivity. They enjoy interactions with their humans and are said to recognize their owners. These lizards can even walk on a leash.

In the wild, females lay around 10-30 eggs at a time. Some dig nests into the bottoms of ant or termite mounds. This way, the ants and termites rebuild around the eggs, making the perfect humid environment for incubation. The eggs usually take around 120-150 days to hatch, but it is not uncommon to take as long as a year.

#4: Perentie

Australia is home to the perentie lizard, Vavanus giganteus. It is the largest lizard in Australia, but they are rarely encountered in the wild because they are reclusive. They also prefer desert-type habitats found in remote regions. Perenties grow to over eight feet long and reach as large as 44 pounds. They are primarily brown with pale blotches edged in a darker brown. These lizards are fast runners and can reach speeds up to 25mph.

Female perenties lay about 6-10 eggs in a burrow or termite mound. The eggs can take anywhere from 3-9 months to hatch, but it is typically over 200 days. The brightly colored hatchlings are able to fend for themselves as soon as they leave the egg. Perenties are believed to live as long as 40 years in the wild.

#3: Crocodile Monitor

The crocodile monitor, Varanus salvadori, is native to Southeast Asia. They can reach around eight feet long and weigh up to 44 pounds. The longest portion of the lizard is the tail, which may be as much as 2/3rds of its body length. The long tail is used as a whip, and the serrated teeth will slice and tear meat somewhat like a crocodile, which is how they got their name. Their bodies are mostly blackish-green with yellow spots.

Due to their reclusive nature, everything we know about their reproduction is based on animals in captivity. Females lay 4-12 eggs up to three times a year. The eggs can take 5-8 months to hatch, and they do not hatch at the same time. It can be as long as four weeks between the first hatchling and the last. In captivity, they are known to live as long as 20 years.

#2: Malayan Water Monitor

South and Southeast Asia is home to the Malayan water monitor, Varanus salvator. The largest specimen on record was around 10 feet long, but most reach no more than eight feet. The maximum weight of this lizard is around 110 pounds. As their name would suggest, they are strong swimmers and use the fin on their tails as a rudder to steer in the water. They can also stay underwater for up to 30 minutes.

Malayan water monitors are a brownish-grey color with yellow spots on their undersides. These semi-aquatic lizards dig burrows along riverbanks. The females lay between 20-50 eggs in rotting logs, stumps, or termite mounds. Incubation takes about 5-6 months. Malayan water monitors are believed to live as long as 25 years.

#1: Komodo Dragon

Weighing in at around 300 pounds and measuring 10 feet in length, the Komodo dragon, Varanus komodoensis, is the largest lizard on Earth. They can only be found on the islands of southeastern Indonesia. Adult dragons are mostly grey with lighter-colored spots. Komodo dragons have a venomous bite that prevents blood clotting, causing its victims to go into shock as they bleed to death. The bite also introduces bacteria from their saliva that may be septic.

Komodo dragons only mate once a year. Female dragons bury up to 30 eggs and incubation takes around eight months. If they are unable to mate, the females can reproduce by themselves. They have both male and female chromosomes, so fertilization is not required. Male Komodo dragons live between 30-40 years in the wild. However, females only reach around 20 years. These lizards are generally solitary and rarely go far from the valley where they hatched.