Asian Water Monitor Lizards in Thailand

Thailand Monitor Lizards

Thailand’s Monitor Lizards – A Brief Guide

Monitors (Varanus Salvator) are some of the world’s largest lizards.  Thailand, along with most of South East Asia, has a large population of water monitor lizards. Elsewhere they are know as Malayan water monitor or the Common water monitor.

These huge reptiles, which can easily reach 2.5m (8 ft) in length and weigh 50+ kg (110+ lbs) can be found inhabiting lakes, rivers, swamps and mangroves across the country.

If you’re lucky you might spot them wandering across roads in National Parks, lazing near paths to waterfalls or even in tree branches.  They are good climbers and can be spotted resting in trees at heights up to 10 meters (30 ft).

Water monitors can swim and run surprisingly fast.  They can also stay underwater for up to half an hour. Which is useful when stealing crocodile eggs or hunting prey, as they are carnivores that mainly eat small creatures such as birds, snakes, rodents and fish.  They are also the only lizard to have a forked tongue, like a snake. It also works in the same way.

Its tongue constantly flicks in and out. This transfers odors to receptors on the roof of its mouth. It can then detect what type of potential prey is in the area.  Because the tongue is forked, the monitor lizard receive information on receptors on both sides of its head.  Helping it also figure out the direction the odors are coming from.

Where to See Monitor Lizards in Thailand?

Asian monitor lizards are found across the country.  As mentioned, they live in various habitats, from mountain streams, mangrove forests, tropical jungle and even some urban areas.  However, most are shy. They tend not to show themselves in areas where there are a lot of human activity.  So seeing them in the wild isn’t guaranteed. 

Here on Koh Chang (where I live) we have a family of them living in the mangroves behind our riverside house.   However, it’s very rare we seen them.  Occasionally I will hear a rustling in the mud and see one disappearing out of sight. 

However, if you want to see a monitor lizard up close and not in a  zoo, there is one place where you’re certain to see them. In Lumpini Park, Bangkok. 

Lumpini Park is slap bang in the centre of Bangkok.  In the middle of the park is a large lake which is also home to many Asian monitor lizards.  It may sound odd that they were allowed to stay in the park, but they help keep the area clean by feeding on trash and dead meat, especially dead fish, birds and other animals.

Back in 2016 it was estimated that there were over 400 living there.  Which prompted authorities to catch the majority and relocate them to an sanctuary in Ratchaburi.  They don’t have any natural enemies in the park and, as they have a lifespan of up to 25 years, their number can grow quickly. 

In the wild, they don’t have any natural predators.  Although, King Cobras have been known to hunt monitor lizards, but thankfully there aren’t any of them in the park.  Given the choice between more monitors or fewer lizards but also King Cobras slithering around, I think most people will choose to have more monitors. :-)  

Asian monitor lizards don’t attack people, but can cause accidents.  There were a few instances of cyclists colliding with them as they crossed the road in the park.  Or veering off the paths when confronted by one crawling out of the undergrowth nearby. Not surprising, as the largest were over 2.5 metres (8 feet) in length. 

There are still a lot of monitor lizards, over 100, in the park. However if you are just strolling around the park you might not see them.  They live in the lake and stay relatively close to it, on the sloping sides by the water.  Virtually out of sight to the thousands of walkers and joggers who frequent the park daily.  They mainly eat fish, birds and turtles. 

So the best way to spot them it to get out on the water.  And to do that you have to hire a pedalo.  These are in the shape of a huge swan and cost 40 Baht for 30 minutes hire.  Which is long enough to work up a sweat and to also see a few monitors.  If you have a good zoom lens then you’ll get some great wildlife photos.  And will be able to convince your friends you ventured way off the beaten track in order to grab the pics.

Lumpini Park Monitor Lizard

Do Thai people like Water Monitors?

There’s a clue in the Thai name for an Asian monitor lizard.  Transcribed into English it’s ‘Hia‘   However, it’s better if you don’t try to use it with any Thai.  This is because it’s also pretty much the worst swear word you can say in Thai.  Be prepared for any argument to seriously escalate, if you call someone a ‘Hia‘.   Some people also believe that just saying the word can bring yo bad luck, such is its negative power.

Despite the name, Thais are divided over whether they are lucky or a curse.  People don’t automatically hate monitor lizards. Some believe that they bring bad fortune and are harbingers of doom.  For example, there have been cases of monitor lizards being released in government offices during times of political turmoil.  In an attempt to bring the bad luck upon the government. 

But there again, there are also people who believe that having a 2 metre long lizard wander into your house is a blessing. Apparently the correct way to handle the situation is to talk politely to the monitor, requesting that it brings you wealth and happiness.   

Are They Dangerous to Humans?

No. Asian Water Monitors don’t hunt or prey on people. Despite their size, they eat much smaller animals.  But like most wild animals, if they feel threatened then they will act to defend themselves.

An angry water monitor will usually first try to escape when it sees humans nearby.  If that doesn’t work and it is cornered, for example inside someone’s home, it will hiss and bare its teeth.  Finally, if there’s no escape or someone grabs the lizard it will try to defend itself.  It can use it’s tail, claws or teeth and all three have the potential to cause a serious injury.  It’s bite isn’t poisonous, but it’s mouth is a hotbed of bacteria.  The bite won’t kill you, blood poisoning might.  Which is why it’s essential to get any monitor lizard bite cleaned and treated with antibiotics immediately.  

However, if a human a grabs or threatens one, it may use its teeth, claws, or tail to defend itself.  All three could inflict significant injury. If you are bitten by a monitor, it is important to clean the wound and apply antibiotic ointment immediately, as rotting flesh in the monitor’s mouth may lead to inflection. You should seek medical attention in the case of any serious bite in order to prevent infection. It is possible that very serious bites from the largest monitors may lead to fatalities.

Asian Monitors as Pets

They are rarely kept as pets here in Thailand.  But Asian monitors can make surprisingly good pets for reptile lovers.  They get to know their owners and once they become accustomed to them, will become more interactive and enjoy attention.  They will be very docile around people they know. 

If you are interested in owning one as a pet, this video goes into much greater details about the pros and cons of having an Asian water monitor lizard as a pet.

Recommended Monitor Lizard Resources:

Wikipedia: Water Monitor
Ecology Asia: Malayan Water Monitor
A Field Guide to the Reptiles of South-East Asia (Book)
Bangkok Herps