Lizards in the monitor lizard family are among the largest lizards in the world.

These reptiles are mainly native to Asia, Africa, and Australia, but can also be found in parts of the Americas due to the illegal pet trade. Monitor lizards are known for their large claws, powerful tails, long necks, and well-developed legs. They can move quickly and powerfully in pursuit of prey. Most monitor lizards are terrestrial and largely carnivorous. Depending on the size of the lizard, they will eat anything from insects and birds to small mammals.

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5 Incredible Monitor Lizard Facts!

• Monitor lizards are considered to be the most intelligent of all lizards and some of the most intelligent reptiles in general.
• Monitors do not blink and they have very good vision. Scientists have observed monitors watching planes in the sky.
• Unlike many other reptiles, many monitor lizards have high metabolisms and burn energy like mammals.
• As pets, monitors have been observed seeking human attention and wanting to play.
• Monitors are alert and skilled predators. As dangerous as they are to smaller animals, their bites are not fatal to humans

Monitor Lizard Scientific name

The monitor lizard belongs to the kingdom Animalia, the phylum Chordata, the class reptilia, the order Squamata, the family Varanidae, and the genus Varanus. There are a number of subgenera for the monitor lizard, including the following:

• Empagusia
• Euprepiosaurus
• Odatria
• Papusaurus
• Philippinosaurus
• Polydaedalus
• Psammosaurus
• Solomonsaurus
• Soterosaurus
• Varanus

The scientific name Varanus comes from an Arabic word that means dragon or lizard beast. The standard English name for the monitor lizard may come from the reptile’s habit of standing on its hind legs to look around.

Monitor lizards have a number of local names depending on where they live. Some standard names for different types of monitor lizards include the following:

• Bengal monitor
• Gray’s monitor
• West African Nile monitor
• Black-throated monitor
• Blue-tailed monitor
• Savannah monitor
• Timor tree monitor
• Crocodile monitor
• Ridge-tailed monitor

The earless monitor is a rare species of monitor that lives in Borneo. It is the only species in the monitor subfamily of Lanthanotinae. It looks much like other monitors with an elongated body, but it has smaller limbs than normal with this species.

Monitor Lizard Appearance

Types of monitor lizards vary widely in their appearance and size. The smallest species of monitor grows to only eight inches in length. However, several species are quite large and can grow to lengths between seven and ten feet. No matter what size they are, monitor lizards tend to have thick, solid bodies, long necks, well-developed legs, and long tails. Colors vary widely with mottled shades of brown, black, gray, green, yellow, and blue being most common.

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Komodo Dragon vs. Monitor Lizard

The Komodo dragon is actually a type of monitor lizard. Its scientific name is Varanus komodoensis. The Komodo dragon is the largest species of monitor lizard, and it can grow up to ten feet long and weigh over 70 pounds. Komodo dragons are also generally known to be the most dangerous types of monitor lizards, and some attacks on humans have been recorded. Komodo dragons look generally similar to other monitor lizards, but they tend to have larger and heavier frames. Most other types of monitors have a more slender appearance. The skin of a Komodo dragon is also unusual compared to other monitors. It has tiny bones called osteoderms throughout its skin, which reinforces the toughness against predators. The dragon’s skin is thus very rugged and rough.

Monitor Lizard Behavior

Monitor lizards are generally solitary reptiles, but in some areas with limited water resources, monitors will gather in groups of up to 25. Otherwise, monitor lizards typically lead solitary lives until they come together to breed. Monitors are mostly terrestrial and move about most comfortably on land–especially with the larger species. There are a few arboreals and aquatic monitor species as well.

Most monitors are completely carnivorous. Monitors are generally shy of humans but can be dangerous if provoked. They are faster than they appear and have strong jaws and tails. Monitors can be very aggressive in protecting their territory or food. Many monitors are active hunters that stalk and chase down their prey. Other types of monitors are more interested in scavenging.

Monitor Lizard Habitat

These lizards are readily found in Africa and Asia as well as islands in Oceania. They can now be found in parts of the Americas, but they are considered an invasive species due to their non-native status. Monitor lizards in the Americas originated from the exotic pet trade. Monitor lizards adapt to many environments. They can be found in jungles and rainforests, but also in aquatic areas and hot and dry areas.

Water monitors like the Asian water monitor live in coastal areas with semiaquatic habitats such as swamps and mangroves. They also adapt to places with canal systems, such as those found in Sri Lanka.

Arboreal monitors like the Timor tree monitor spend most of their time in trees. They have long tails and sharp claws that are well-suited to climbing through branches and trees.

Monitor Lizard Diet

These lizard’s diet depends on where the reptile lives as well as its size and type. Tree monitors tend to eat insects and birds. Some species of tree monitor eat mostly fruit. Water monitors tend to eat anything they can find in the water. This includes fish, water birds, insects, eggs, and water mammals or reptiles. These lizards that largely live on land, such as the Komodo dragon, may eat a wide variety of live prey as well as carrion. The diet of the Komodo dragon consists of about 50% deer native to its island. Komodo dragons are also known to eat pigs and cattle if they can get them. These lizards are very opportunistic predators.

For a complete analysis of what monitor lizards eat, we’ve published ‘What Do Monitor Lizards Eat? 11 Foods in their Diet.’

What eats monitor lizards?

Large adult monitors have few predators. Smaller and baby lizards may be eaten by birds, other reptiles and lizards, wild cats, and humans.

What does a monitor lizard eat?

A wide variety of food including fruit, insects, birds, fish, mammals, and reptiles.

Monitor Lizard Predators and threats

For the largest species of these lizards, the main predator is humans. Some types of monitors are hunted by humans for their skin in the leather trade. The only exception to this is the Komodo dragon, which has rough and rugged skin not suitable for leather. For all types of monitors, the young lizards are preyed on by other lizards, snakes, large birds, fish, and big cats. Smaller lizards are also preyed on by these animals both when they are young and when they are adult size.

The conservation status of these lizards depends on the species. For example, the Komodo dragon is considered vulnerable. On the other hand, the Asian water monitor has a conservation status of least concern. The Panay monitor lizard is considered endangered. These lizards mainly lose their numbers due to threats to their habitat, decreasing water resources, and hunting from humans.

Monitor Lizard Reproduction, Babies, and Lifespan

Males will often fight to mate with females. The Komodo dragon usually mates between May and August, and eggs are then laid around September. Female lizards are often antagonistic towards the male, which means the male has to fully restrain them during mating or they may get injured.

These lizards typically lay their eggs in a concealed nest in the ground. They might also lay them in hollow tree stumps. The exact method differs depending on the species. For example, the Komodo dragon might lay its eggs in abandoned ground bird nests, or they might lay them in holes in the ground or hills. Some monitor species can lay as many as 30 eggs. Komodo dragons lay about 20. Nile monitors have a clever way of laying eggs where they dig them into termite mounds. The termites will naturally cover the hole, thus providing a secure and warm place for the eggs. When the eggs hatch, the baby lizards often eat the termites before leaving the mound.

As young lizards and unhatched eggs are attractive to many predators, not many young lizards survive from the original clutch. Young land monitors may spend much of their early life in trees to avoid predators.

Most of these lizards can live at least 20 years. Komodo dragons may take as long as nine years to reach full maturity. They can live up to 30 years. Larger monitors tend to live longer than smaller species.

Monitor Lizard Population

There are roughly 80 species of these lizards in the world. The smallest species live in trees or water, and population data is unknown for most of these. The rare earless monitor lizard is an example of unknown population data. It’s considered vulnerable due to its small range. However, the earless monitor is nocturnal and is not often seen by locals. Many of the smallest monitors have unknown data. Large species like the Komodo dragon are protected in some areas to keep their numbers from dwindling. Loss of food sources and habitat are the main reasons for monitor populations going down. If food and habitat are plentiful, then monitor populations in these areas tend to increase.

Monitor Lizard In the Zoo

There are plenty of zoos across the country where you can see Komodo dragons and other monitor lizards, including the following:

• Bronx Zoo
• Louisville Zoo
• Fort Worth Zoo
• Toledo Zoo and Aquarium
• Smithsonian National Zoo
• Pittsburgh Zoo

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