Discover the Largest Monitor Lizard Ever

Animals that reproduce asexually – Komodo dragon
Anna Kucherova/

Written by Cindy Rasmussen

Published: January 2, 2022

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Monitor lizards are a group of lizards that belong to the Varanidae family and are considered the largest lizards. They look similar to crocodiles with long bodies and scaly skin, but they are much heavier than crocodiles and have thicker legs and a stronger tail. Monitor lizards live on land and can move quickly despite their size. As carnivores, they hunt for their prey and can viciously attack birds and small mammals with their large claws and sharp teeth. Some monitors are also venomous and use the venom to stun their prey before devouring it. The three largest monitor lizards are the Komodo dragon, Asian water monitor and crocodile monitor. Let’s take a look at these amazing lizards!

3.) The Crocodile monitor is the third largest monitor lizard

Crocodile monitor

Crocodile monitors are the third largest monitor lizard and can grow up to 200 pounds.

Crocodile monitors are found in New Guinea and live among the mangrove swamps and rainforests. They have long necks and long tails with their tails making up half of their length. From nose to tail tip these lizards can grow to be 7-9 feet and can weigh as much as 44 lbs. One unique characteristic of these lizards are their teeth. Crocodile monitors have a mouth similar to crocodiles and have flat, serrated teeth vs the sharper curved teeth of most monitors. They use their teeth for tearing their prey in a similar way as other monitor lizards.

2.) The Asian water monitor is the second largest monitor lizard

What do monitor lizards eat - water monitor being fed

Water monitor lizards are the second largest species of monitor lizard.

The Asian water monitor, or sometimes called common water lizard, can be found in the Greater Sunda Islands and from Sri Lanka to southern China. They are active hunters and are excellent at swimming and climbing making it difficult for prey to get away. Asian water monitors also have no problem feeding on carrion and have been known to even dig up human remains. These large lizards can grow to be 9 feet long and weigh 110 pounds.

1.) The Komodo dragon is the largest monitor lizard

Komodo dragon hunting

Komodo dragons are the largest species of monitor lizard and have reached 365 pounds in size.

The largest monitor lizard in the world is the Komodo dragon. The largest Komodo dragon on record was displayed at the St. Louis Zoo and weighed 365 pounds, making it twice as large as the average Komodo.

With the word “dragon” in its name it is no wonder that these lizards are the largest of the monitor lizards. Komodo dragons are fierce creatures and are from the Indonesian Island of Komodo. They reach their adult size when they are around 9 years old with males averaging 8 feet 6 inches and weighing 175-200lbs and females getting to be 7 feet 6 inches and weighing 150-160lbs. Some have theorized that the Komodos have gotten so big over the years because they do not have any predators on the secluded island in which they live.

The largest extinct monitor lizard (It was huge!)

Monitor Lizard Facts - Megalania

Megalania was the largest extinct monitor lizard and could reach up to 23 feet in length.

The largest extinct monitor species was named Megalania and it reached 23 feet long. Its estimated that Megalania could have exceed 4,000 pounds, making it about 20 times the size of the average Komodo dragon and 10 times larger than the largest Komodo dragon ever!

Surprisingly, Megalania only went extinct about 50,000 years ago. The giant monitor lizard lived in Australia and would have been a terrifying sight in a country that already features gigantic saltwater crocodiles!

Where can I see a giant lizard in person at a zoo?

If you are having a hard time imagining how big a 10 ft lizard is perhaps you would want to see one for yourself. Following are zoos that have these giant lizards on display:

  • Louisville Zoo, Kentucky
  • Toledo Zoo & Aquarium, Ohio
  • Pittsburgh Zoo, Pennsylvania
  • Smithsonian National Zoological Park, Washington D.C.
  • Bronx Zoo, New York

Monitor lizard fun fact

In contrast, the smallest monitor lizard is a lizard from Australia. The short-tailed pygmy monitor is only 25cm (9.8 inches) long. If you looked at a picture of one you would not think that their tail is particularly short, they look similar to other monitor lizards but are smaller in size. As babies (they hatch from eggs) they look just like adults but a smaller version starting out just an inch or two!

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About the Author

I'm a Wildlife Conservation Author and Journalist, raising awareness about conservation by teaching others about the amazing animals we share the planet with. I graduated from the University of Minnesota-Morris with a degree in Elementary Education and I am a former teacher. When I am not writing I love going to my kids' soccer games, watching movies, taking on DIY projects and running with our giant Labradoodle "Tango".

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