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The Asian Water Monitor Lizard; Varanus salvator

Alun is a frequent visitor to Thailand and writes personal accounts of the country's great attractions in a series of easy-to-read articles

The Asian Water Monitor

The Asian Water Monitor


This page tells the story of Varanus salvator, the Asian Water Monitor lizard, which today is one of the most readily accessible large reptiles on this planet - an animal which can be seen in many locations of southeast Asia where water is abundant. We look at the creature's life history, its habits and physical appearance.

This article refers specifically to the water monitors to be found in a large public park in Bangkok, Thailand, where they form a memorable and unusual tourist attraction.

N.B: Please note, all my articles are best read on desktops and laptops

All photos were taken by the author in Lumpini Park in Bangkok. Lumpini Park is also the subject of another webpage by this author, which can be found in the links at the foot of this article.

On hot days (in Bangkok that is most days!) monitors will bask in the sun

On hot days (in Bangkok that is most days!) monitors will bask in the sun

The Dragons in the Park

Lumpini Park in the capital metropolis of Thailand, the City of Bangkok, is a green and pleasant open space in the urban sprawl. The lungs of the city, Lumpini Park is a landscaped garden of ornamental flowering trees and carefully manicured and well watered lawns and flower beds. In the middle is an attractive boating lake with fountains. Bangkok residents and tourists alike will come to this park to relax away from the noises and smells of the city, to stroll along the walkways, to jog and exercise, or just to sit and contemplate and while away the hours. And because this is a haven of tranquility and beauty, the visitors expect to share their park with attractive flower beds and graceful butterflies and cute little squirrels and pretty song birds, and of course - enormous six foot long reptiles.

Six foot long reptiles??!!! Yes indeed. There are few places in the world where such outlandish modern day dragons can be found in close proximity to humans. But thankfully you don't need to be a modern day St George to survive here, and these dragons certainly don't need slaying. They are a species of monitor lizard, and they are indeed closely related to and quite similar in appearance to the infamous and lethal Komodo Dragon of Indonesia. But there the similarities end. Though theoretically capable of harming a very small child, in practice the lizards in Lumpini Park seem inoffensive and would much rather slip gently away into the water the moment a human being gets too close; I am not aware of any incidents of aggression being recorded in the park.

As with snakes the long forked tongue of the lizard is used to smell out its prey

As with snakes the long forked tongue of the lizard is used to smell out its prey

















V. salvator


Water Monitor

The Classification of Varanus Salvator, the Water Monitor

All animals which possess backbones are included in the Phylum Chordata. The Chordata comprises five main living groupings or 'Classes'. These classes are the Fish, the Amphibia, the Birds, the Mammals, and the Reptilia, to which Varanus salvator belongs.

The Reptilia consists of four divisions or 'Orders' the members of which all have similar characteristics to each other, and one of these orders is the Squamata which incorporates the snakes and lizards. All lizards belong to the Suborder Sauria, and monitors are to be found in the Family Varanidae.

One can get very close to these lizards if one keeps low in the grass

One can get very close to these lizards if one keeps low in the grass

The Breeding Cycle

The breeding cycle of the Asian Water Monitor begins around April in regions with pronounced wet and dry seasons, and may continue until October. But in regions without a wet season, breeding may occur at any time of year. Each female produces up to 40 eggs per year, but usually these will be in two or more clutches laid in natural mounds such as termite hills, or in rotten or hollow tree trunks or in excavated burrows. Good, well protected sites may be communally used by several lizards. Usually the nest will be covered over after laying. Incubation takes several months though this can vary considerably according to the climate and the season of laying - an adaptability which has greatly assisted the lizard's widespread distribution throughout southeast Asia.

Hatchlings are about 30 cms (12 ins) long. Juvenile lizards are quite brightly coloured with yellow blotches against a darker background and yellow bands on the tail. These young monitors tend to be more timid than adults and hide away rather more. Usually it will take about 2 years to reach maturity, and adults can then live for about 15 years.

Read More From Owlcation

The water monitor, as its name might suggest, is a powerful swimmer

The water monitor, as its name might suggest, is a powerful swimmer

Facts About Varanus Salvator

Varanus salvator is the most common species of monitor lizard to be found on the continent of Asia, occurring all through the southeast from India and Sri Lanka to Malaysia, Indonesia, Borneo and the Philippines - the widest range of any species. Water monitors can attain a length of 3m (10 ft), and a weight of more than 25kg (55 lb) making them genuinely alligator-sized creatures, and one of the very largest species of monitor after the Komodo Dragon. It must be said however, that the great majority including those in Lumpini Park are much smaller - between 1 and 2m (3 ft to 6 ft) in length.

The adult water monitor typically has a muscular brown-grey body with light patterning along the flank, and a pale underside. Patterning may vary within different subspecies. Water monitors have a characteristically long and narrow head and neck, and a long and laterally compressed tail.

This species V. salvator, should not be confused with the similarly named V. salvadorii - the crocodile monitor - a quite different species which lives in New Guinea.

V. salvator is quite a sight as it emerges like a dragon from the depths

V. salvator is quite a sight as it emerges like a dragon from the depths

There is something primordial about the appearance of these creatures

There is something primordial about the appearance of these creatures


Most active in daylight, V. salvator tends to lead a solitary life, but these lizards are not particularly territorial. Usually the days are spent basking in the sun, or hiding away in burrows dug into river and lake banks. These burrows may be excavated deep into the ground and may be up to 9m (30 ft) long. However in Lumpini Park, the lizards make good use of artificial man-made burrows - the drainage water pipes which regulate the lake's supply of water.

Swimming, unsurprisingly, is the forte of the Asian Water Monitor, and with their powerful tail swayed side to side like a paddle and their legs tucked in along the side to streamline the body, these lizards are capable of traversing large bodies of water. This has enabled them to occupy many islands in the Indian Ocean, the Andaman Sea and the Indonesian archipelago. Typically their aquatic behaviour means that they are to be found along shorelines and mangrove coasts, but also in rivers and inland lakes. However these most adaptable of creatures are also at home on dry land, some distance from water, and at altitudes of up to 1,000 m (3,300 ft). They are also quite capable climbers - a versatility which undoubtedly helps in their success as a species.

Most species of Varanus are exclusively carnivorous, and Varanus salvator is no exception. It certainly isn't fussy about what it eats either. Anything it can cope with is fair game, including insects and snails, fish and frogs, birds and small mammals, and reptiles including young crocodiles. On land, their powerful leg muscles are used to chase and hunt down prey, and their climbing ability enables this species to raid birds nests too. But of course the monitors are equally adept at pursuing prey in their favoured aquatic habitat. And they will also scavenge when the opportunity arises, without too much concern over the freshness of the carrion.

In turn, the monitors may be hunted by larger crocodiles, and juveniles may be vulnerable to birds of prey and large water birds such as herons. In some rural localities they are also be used as a source of food by humans. To escape from predators a monitor can remain submerged for long periods of time (up to half an hour). But away from water it will run with alacrity, hide under vegetation, climb trees, or utilise the burrows and holes which are its preferred shelter on dry land.

Varanus salvator is often to be seen at water's edge

Varanus salvator is often to be seen at water's edge

A Creature to Cherish

The status of the Water Monitor in the world today - like all animals - is impacted upon by the presence of man. Loss of habitat is of course a major problem. In some locations numbers have declined considerably through hunting for skins to be made into fashion goods. Potions are made too out of various body parts for sale in the far East as aphrodisiacs, skin ointments and medicinal tea. Roadkill is also a significant factor in lizard deaths.

However despite these negatives, this remains one of the region's most successful wild animal species. In some countries such as Thailand, the lizard is protected by law. In addition, high reproductive rates, the ability to rapidly spread and colonise new land though its swimming prowess, tolerance of different climates and the incredible adaptability of the species to a wide range of conditions and food supplies, have all contributed to its level of success. What's more, as we have seen, the monitor in safe environments has no problem living next door to man.

Varanus salvator in Lumpini Park, Bangkok, is a tame and a remarkably common creature. One only has to spend an hour wandering the edges of the ornamental lake to be sure of seeing a dozen or more. But Lumpini Park is not unique in this regard. In these days of sanitised living conditions in which humans live closeted lives and wildlife is kept strictly in its place, one usually has to travel very far, and sometimes to fenced off nature reserves, if one wishes to see the more impressive members of the animal kingdom. Therefore, although a giant lizard may not be a creature to love, it is certainly a creature to cherish as one of the most exotic of animals readily seen in tropical Asia. Anyone with an interest in wildlife should make the effort to seek out the water monitor. In Lumpini Park in Bangkok, it is easy to do this, but wherever one lives or visits in southern and eastern Asia, the Water Monitor is undoubtedly one of the wildlife sights to see.

A common sight in Lumpini Park

A common sight in Lumpini Park

Please feel free to quote limited text on condition that an active link back to this page is included


Lumpini Park

© 2012 Greensleeves Hubs

I'd Love to Hear Your Comments. Thanks, Alun

Greensleeves Hubs (author) from Essex, UK on August 09, 2018:

Aashritha: Not really underground, Aasritha, but they will burrow for protection of themselves or their eggs. Most of their activity however is above ground, hunting and basking in the sun to get energy from the sun's rays.

kratos ferno; Thank you for that comment, and I hope you have success with your school project. Water monitors certainly make an interesting subject to write about! Alun

Apologies to kratos ferno and Aashritha for not replying sooner. Alun

Aashritha on June 14, 2018:

So are they underground lizards

kratos ferno on June 12, 2018:

water monitors are one of the coolest creatures in the world and also I am doing a Water Monitor for a school project.

Greensleeves Hubs (author) from Essex, UK on January 17, 2018:

Eric vois morris; Sorry I could not reply earlier Eric. It is probably too late for me to offer advice to you now, but for anyone else who experiences a bite from a water monitor, I suspect the only advice is to seek medical help (a vet in the case of a pet).

As far as I'm aware there are no specific dangers - I do not think, for example, that they carry rabies, though I stand to be corrected on that. Bites by Asian Water Monitors are extremely rare given their close proximity to human beings. However some relatives (most notoriously the Komodo Dragon) do have a bite which contains venom (NOT toxic bacteria causing blood poisoning as previously thought) and it is of course prudent with any wild animal to seek medical attention after a bite.

Eric vois morris on December 18, 2017:

omg i found a water monitor in my back yard it hurt my dog what should i do i need to know??????

Eric vois morris on November 28, 2017:

well id love to study a monster animal

Greensleeves Hubs (author) from Essex, UK on July 17, 2017:

Rufiel Maravilla; Thank you Rufiel. It is difficult to advise, but I will try. I am guessing you are in S.E Asia? If so, I think it is very possibly a water monitor in your home. These lizards are not really dangerous, but it can bite if it feels threatened, and if it bites you, it can cause a blood infection due to germs in its mouth. So I certainly would advise against handling it.

If you can carry it outside (in the basket) safely, maybe you can release it away from the home, near water? If not, can you call someone - an Animal Rescue Service?

Rufiel Maravilla on July 16, 2017:

I found a lizard on my garbage basket in my room today and it looks like a monitor lizard same appearance from the photos above...i want to touch it but i am afraid,maybe it can bite me..?i want to take good care of it...can you give me some advice please?what to do?

Greensleeves Hubs (author) from Essex, UK on October 02, 2014:

Chauncey St Clair; Thanks! I'm sure it's true that these water monitors play a valuable role in clearing pest species and also scavenging dead animals which would otherwise be a potential source of disease. But I can see how the similarity to a Komodo Dragon would cause negative connotations. I don't know if there's ever been a serious problem with them as they seem very inoffensive - unlike the Komodo - but I don't suppose it's a good idea to be bitten by one, as they may have harmful bacteria in the mouth! Cheers, Alun

Chauncey St Clair from New York City on October 02, 2014:

When I was living in Sri Lanka for a brief period of time, they were everywhere and the locals loved them. They were quite good at keeping rodents and pestilence at bay. Personally, they reminded me too much of the Komodo and triggered my great fear of being bit by one!

Greensleeves Hubs (author) from Essex, UK on December 22, 2013:

Pocono foothills; I guess the lizards in Mexico were probably iguanas? They are I think the New World equivalent of Asian monitor lizards both in terms of size and general behaviour. Some can indeed be pretty impressive, and make for an interesting tourist attraction by the swimming pool or on the beach! My thanks for your visit and comment and for those votes! Alun.

John Fisher from Easton, Pennsylvania on December 22, 2013:

@Greensleeves Hubs-Very informative Hub and lots of great pictures. When I visited Mexico, we frequently had large lizards basking in the sun by our swimming pool. They looked scary, but they never bothered us. Voted up!! Great Hub.

Greensleeves Hubs (author) from Essex, UK on April 05, 2013:

lesliebyars; my thanks and gratitude for the compliments, the votes and tweets. It was a pleasure to write this page and share the experience of these great reptiles which I've seen on several occasions in Bangkok. Alun.

lesliebyars on April 04, 2013:

This hub was great and the pictures were truly amazing. Voted up and tweeted.

Greensleeves Hubs (author) from Essex, UK on February 25, 2013:

Alfred; regarding the turtle - not nice to think about!! I had fried insects once in the village where I was a guest of a Thai family (which I write about in another hub:

But perhaps they were kind to me because I did not witness any other wild creature (apart from fish) being killed. Chickens were of course also kept for food. Thanks for the info :-)

Alfred Hoeld on February 24, 2013:

Yes for food, sorry.

When you have been in TH and Isaan, you know, the Thais hunt everything and eat nearly all things!

Big Lizards, frogs, snakes (special pythons), turtles of all kinds, rats, bats-flying foxes, eggs of red ants, silkworms, all kinds of insects.

Regarding turtles, I passed by a house in the village slowly once and my eye had to realize, the already nearly finished chopping of a big turtle.

I think a kind of "Snapping Turtle" only her long neck and the head was not chopped and still, the poor animal opened her mouth and the eyes looked at me. :-( Bon appetite

Greensleeves Hubs (author) from Essex, UK on February 23, 2013:

Alfred; thank you for your visit and for that story. I know Isaan and Udon Thani well because I too have spent time in a village there, but have not seen water monitors killed there. For food? It's a shame to see wild creatures killed in that way. A full grown live lizard is a very impressive sight to see, for anyone interested in nature.

Nice to see you on HubPages. Alun.

Alfred Hoeld on February 23, 2013:

Sadly, I just saw today morning, one nice, long, 1,50 m? -Monitor Lizzard- already dead, put in a fire in the small Village I stay, in Isaan, North Eastern Thailand Province of Udon Thani.

The Group of men showed it to me same a trophy. I felt sorry!

Two chickens provide more meat than that creature I think!

Why have to kill? So good? ;-( I never saw a Reptile that size free moving in TH, only once an even bigger one 20 years ago in Sri Lanka!

Greensleeves Hubs (author) from Essex, UK on November 19, 2012:

Wow. That's certainly a dramatic video Sylvain. Makes the water monitor look like a dinosaur! I'll happily retain the link to your video for people to view. Maybe in due course I could incorporate it into my web page. Alun.

Sylvain Hugues on November 19, 2012:

DRAGON : Monitor lizard in Lumpini park

My video :

I bought meat balls in the street to tease it, waying a meat path for dragons to my camera.I put the camera down attached to a stick with robber, then I stood 20 meters from the scene. Dog started to come as they smelled sthing good, I have to busy them with other meat balls. I saw the dragon covering up my camera. Magiiiiic, it s like a star wars spaceship.

Greensleeves Hubs (author) from Essex, UK on November 11, 2012:

Thank you precy! Glad it brought back memories for you. I'm sure these very successful lizards must be common in much of the Philippines just as they are in Thailand and other countries in the region. We who live in colder climates miss out on some of these experiences unless we go on vacation! Thanks so much for sharing. Alun :-)

precy anza from USA on November 10, 2012:

Great information about the monitor lizards Alun :) And they reminds me childhood memories. Had seen them visiting our yards as we live near a river back then. Voted up and shared!

Greensleeves Hubs (author) from Essex, UK on November 04, 2012:

AliciaC, thank you very much for your generous comment about this hub. It's much appreciated. It was an enjoyable hub to write, as I've come to know these lizards quite well during several visits to Bangkok. Alun.

Linda Crampton from British Columbia, Canada on October 30, 2012:

This is a fascinating hub, Alun, and the photos are wonderful! Thank you very much for sharing the information about this lizard in such an enjoyable and beautiful article.

Greensleeves Hubs (author) from Essex, UK on September 27, 2012:

Mandy; Many thanks for that interesting little story. Certainly I can believe that the monitors may shelter in the roof - they are obviously capable of climbing up there and it seems like a very safe place to hide out! With the canal nearby, it seems like an ideal locality. I'm not sure whether there might be other candidates for the scratching sounds you hear, but water monitors in the roof must be a possibility. Thanks. Alun.

Mandy on September 27, 2012:

I just came across your hub to research a bit about these guys as we have a number of them living around our house here in Bangkok. Since moving in a few months ago we have been catching sight of at least 5 of them ranging from a foot long up to 1.5 metres. We have vacant plots both sides of our house and a canal directly behind us. Just this moment the dogs started barking at something outside the upstairs window. I couldn't believe it! there he was, the big one (1.5 metres long), perched in the tree (and this was quite a thin tree). He looked like he was heading for the roof. Took some quick photos before he threw himself out of the tree and back into the canal. We do hear a lot of loud scratching and scurring inside our roof (we live in a house which has a traditional thai roof). Do you think these fellas would hide out up there?

Greensleeves Hubs (author) from Essex, UK on September 01, 2012:


Thanks for the visit Eddy and thanks for the warm comment. I think the water monitors are one of the more unusual sights of Bangkok, which anyone who's not too squeamish should take the opportunity to see. Really glad you liked the page.

Enjoy your weekend too. All the best. Alun.

Eiddwen from Wales on September 01, 2012:

A great hub and well informed and as always this in turn led to myself learning more from you.

Thanks for this gem and enjoy your weekend,

Enjoy your weekend.


Derdriu on August 27, 2012:

Alun, Yes, it's the iguanas. There's an interesting article in the Wall Street Journal's issue of August 19, 2012, which is available in print and online.

Respectfully, Derdriu

Greensleeves Hubs (author) from Essex, UK on August 27, 2012:

Thanks Derdriu for your comment. Interesting to hear about the problem Puerto Rico has - Would it be Iguanas in that part of the world? It seems to be the case that some of the larger lizards have developed a lifestyle and tolerance of a range of conditions which enables them to thrive where many other creatures struggle. Alun.

Derdriu on August 27, 2012:

Alun, Puerto Rico is being overrun for 6+ feet-long lizards, to the extent that there are more lizards than people! The lizards have no culinary interest on the island even though they are considered delicacies in Central America and the Caribbean. Puerto Ricans did not favor the government's suggestion of bounty hunting. Now entrepreneurs are trying out killing them to ship out as food exports to the mainland!


Respectfully, and with many thanks for sharing, Derdriu

Greensleeves Hubs (author) from Essex, UK on August 22, 2012:

Thanks Lightshare for your comment. I appreciate it. Alun.

Lightshare on August 22, 2012:

Thanx green for an informative hub. Pictures also good.

Greensleeves Hubs (author) from Essex, UK on August 19, 2012:

Thanks very much Mama Kim! And thanks also for your giraffe story, though not for the mental image it conjures up - not sure I'm sufficiently devoted to wildlife to watch a giraffe picking its nose for 20 minutes, but maybe I'll put it to the test one day!! Apart from that interesting aside, I'm especially glad you say the article is not 'too textbook' - it's usually my aim to keep these kind of hubs fairly light in nature, so thanks for that.

I do slightly wonder about the water monitor's 'scaryness'. Given that it's carnivorous, I wonder if these lizards ever pose a danger to human beings. Maybe the lizards are removed once they get too big, but certainly in the case of the lizards in Lumpini Park (maximum 6 ft long), I haven't seen one show the slightest sign of defiance or aggression to people of any age - they either ignore people or keep 5-10 feet distance from people before running or swimming away.

Anyway, cheers again; I appreciate your comments. Alun.

Sasha Kim on August 19, 2012:

I just love learning about animals! If I had cable I'd have it on constant animal planet ^_^ But then I'd get sucked in and never leave the couch... I mean I could seriously watch a giraffe pick it's own nose with its tongue for 20 minutes and not get board (true story) ... anyways I'm getting off topic... Just looking at the pictures I would think this thing is scary and I hope I never see one in person. However your hub made it much more endearing. I love all the great info you fit in without sounding too textbook. Wonderful job voting up and interesting ^_^

Greensleeves Hubs (author) from Essex, UK on August 17, 2012:

Thanks Glimmer Twin Fan. For me, as a wildlife enthusiast, these monitors have always been a welcome sight whenever I visit this park which is something I usually do when I spend a few days in Bangkok. I appreciate your comments. Alun.

Claudia Mitchell on August 17, 2012:

What an interesting creature and hub. Great photos and loaded with information.

Greensleeves Hubs (author) from Essex, UK on August 17, 2012:

whowas; Thank you so much for that warm and generous comment. I really appreciate it, and thanks so much for the votes and shares.

Certainly the fact that these lizards are so at home on land, and in fresh water and sea water and even climbing trees, and the fact that they can adjust their life history to so many climatic and environmental patterns, gives them an adaptability which - as you say - enables them to survive and thrive in today's human dominated world. Equally, you are so right to imply that even successful species can rapidly deteriorate in numbers if the balance tips too far in the wrong direction. I hope that doesn't happen with the water monitor.

My thanks again, Alun.

Greensleeves Hubs (author) from Essex, UK on August 17, 2012:

Jackie: Thank you for your visit, and very kind comment. Lizards don't get a particularly good press, but they are fascinating animals. Cheers, Alun

whowas on August 17, 2012:

WOW! What a gorgeous hub - fascinating information beautifully written and exquisitely presented with amazing photography. This is one of the best natural history hubs I have ever read. Stunning. And such astonishing creatures, too.

These are surely among the most beautifully adapted reptiles whose naturally evolved behaviors permit them to survive, even thrive, despite the many threats to their wider environment. Even so, we should not be complacent about their plight but strive to preserve for them their natural habitat.

I loved this - voted up, ticked and shared.

Jackie Lynnley from the beautiful south on August 16, 2012:

This awesome! Creepy but awesome. Lot of great info. Interesting and useful.

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