December 8, 2022

Monitor lizards in Thailand: Your FAQs

Seen a massive monster lizard or just wondering what’s out there? Meet the Southeast Asian water monitor.

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Monitor lizards on Koh Samui

Since I first posted about Koh Samui monitor lizards in 2013, I've learned a lot – and some of my readers have kindly shared their lucky lizard sightings, in all sorts of different locations. High time for an update, and some recent reader photos of their monitor lizards.

Monitor lizards on Koh Samui
I can swim really, really fast

Coming to Koh Samui to relax and nap on the beach? Today I share an email from a Koh Samui Guide customer, who kindly wrote in with his story. It might inspire you to keep your eyes wide open as you explore the island. There's so much more than sunny beaches.

Koh Samui monitor lizard story #1

Koh Samui monitor lizard
"One exciting moment we had was nearly colliding with a 1-meter long monitor lizard" – Rick

We enjoyed our trip and your guide very much. One exciting moment we had was nearly colliding with a 1-meter long monitor lizard that popped out into the road in front of us. This was between Choeng Mon and Big Buddha, on the more northerly road. Unfortunately, we didn't have a chance to get our camera out in time.

While there, we did a bit of internet searching to see where these creatures might be spotted more regularly. Only came up with a post on a reptile forum from someone who saw them frequently as she crossed a stream between her hotel and the beach. She didn't say which hotel or which beach. In the event we return to Samui (and I believe we will), any idea where we might spot some of these enormous lizards in their environment, without putting ourselves in harm's way? Thanks, Rick

Monitor lizards in Thailand?

Koh Samui monitor lizard

I have no natural predators ... and Thai people don't like meCertainly, I'd read that "they're out there in the jungle", but I was surprised to hear that monitor lizards can be spotted near inhabited areas, too. So I started some research - even headed to the library - and asked all of my Thai friends. (Response? Total disinterest – rather like asking a Londoner “tell me more about that fascinating native bird of yours, the magnificent pigeon?”)

Meet the Southeast Asian water monitor

The common name in Thai for monitor lizards invokes horrible luck – to demonic proportion.' The reptile forum that Rick kindly supplied identifies the Samui monitor lizards as 'Varanus salvator macromaculatus', or the Southeast Asian water monitor. There's been little scientific study of this Thai sub-species, as its name is associated with a strong insult. Put politely, in the olden days, these scavengers ate the chickens and small livestock of farmers; bad news in meagre times.

On the 'spectrum of beloved animals', put a golden retriever puppy at one end ... and then walk to the other end of the earth.

The water monitor is the lowest of the low – which might explain why my inquiry to Thai friends was met with little enthusiasm, bored shrugs and (in one case) actual repulsion.

No natural predators

Though no one has specifics (see above – near-total lack of domestic Thai study) - water monitors are protected in Thailand and have no natural predators. As such, they're prolific across most of Thailand, though are less known in the north.

Southeast Asian water monitor
You'll likely spot water monitors in or near Bangkok's canals

They can swim faster than you

Much faster. These ugly-muglies are strong swimmers and will swim and hunt in ocean waters. They can move very quickly through water – so quickly that they can steal and eat crocodile eggs, and get away with it. Here's a dinnertime fact: water monitors can stay underwater for up to half an hour.

Colour differences

The difference in markings is a regional thing, though the creatures within are same-same. For example, yellow circular spots are more common in Thailand, while the uniformly brown/grey monitors are found from southern Thailand through Malaysia and Indonesia.

While monitors might usually be a mundane sight for locals (except when they try to get inside your house or rob 7-Eleven shelves), it's always exciting to spot something that's new to you – isn't it the whole point of travel? So keep your eyes peeled as Koh Samui's monitor lizard population is alive and well.

Monitor lizard FAQs

Koh Samui monitor lizard
Yellow circular spots are more common in Thailand

How common are water monitors?

Throughout the region – fairly common. While no figures exist for Koh Samui monitor lizards, they're regular roadkill in Malaysia and, of the Singapore Zoo, the New York Times explains: "if you spot a water monitor long-tailed macaque, know that they're not zoo residents -- just locals looking for a free meal."

Are monitor lizards venomous?

Not exactly. As with most wild animals - they'd rather have nothing to do with you, and will only attack people out of defence. Like Komodo dragons, their saliva has terrible bacteria and victims (including prey) die from a bite's resulting infection. (A video of monitor lizards at the London Zoo shows zookeepers using venom defender gloves to handle the reptiles).

How big are monitor lizards?

Adult water monitors average 1.5 metres long, or just shy of five feet. However, another source puts them at 2.5 metres long – let's agree they're roughly as long as us and that you probably don't want to get close enough to measure.

Readers' monitor lizard sightings

Koh Samui monitor lizard tracks
A reader's photo from Taling Ngam beach

A few months after Rick's note, I had another email from Harry, who was staying on the southeast side of Koh Samui, near Lamai. He too had a monitor lizard sighting:

Koh Samui monitor lizard story #2

About 200 metres from Buddies [*Ed. note: now Manathai Resort Koh Samui, formerly Buddy's Oriental Samui Beach Resort], going towards Lawang village. You cross a stream to get there. There are 2 resident monitors. One about 1 meter (female?) and 1 about 1.3-1.5 (male?) when we have been on the bridge in early evening we have spotted them immediately both times. Great to watch. – Harry

Harry also had some great luck spotting unusual birdlife – so I've duly updated the birds of Thailand page as well.

Koh Samui monitor lizard story #3

We just returned from a trip to Ko Samui last week and spotted a huge black/brown specimen on the rocks by the sea below our hotel. Sadly I did not manage to get a photograph. We were located right at the N/E tip of the Island near Bophut at Dining on the Rocks. Thought it worth sharing! – James

James also added that the lizard was "stomping around on the rocks. Definitely a throwback to the dinosaur era! A pleasure to see such an animal".

Koh Samui monitor lizard story #4

f you are still interested in the lizards, we saw one, about 0.75m long, this afternoon. About half way from the cross roads on the "Ghost road" (Had Chaweng 6), towards the top of the hill near the International School. The chap on the motor bike in front of us swerved as he saw it start to run out into the road. – Tony

Koh Samui monitor lizard story #5

Just wanted to say that my wife and I are staying at the Am Samui resort at the Taling Ngam beach, my wife saw a monitor lizard today were the river enters the see. He ran of immediately, so she didn't get a picture, but later took a photo of his tracks. – Anonymous

"I saw no fewer than 35 or so, very possibly even more" – Jesse

Bangkok tip

If any of your readers would like to see one while they're in Bangkok (a place many of your readers are likely to go I'm sure), to look no farther than Lumphini park. I walked around the park for roughly an hour and a half and saw no fewer than 35 or so, very possibly even more. I saw all sizes, from babies not much more than a foot long, to the full grown ones (according to your article) at about 5 feet. They seemed very used to humans. You could usually get within a few feet of them for a photo before they would slink off into the water. I even saw one with no tail, which makes me wonder if monitors, like many other lizards, can regrow their tails. – Jesse

Most recently, Rachel spotted a monitor lizard in Lamai, Geoff saw a monitor enjoying a beach day at The Tongsai Bay and Samar saw his hiding in plain sight at Bangkok's Damnoen Saduak floating market. Thanks to all!

Me? I’ve spotted a big boy at The Tongsai Bay and more than a few on Bangkok canal tours.

Worth reading

Koh Samui Monitor Lizards

Have you seen something unusual on Koh Samui? Let me know or tag it in an Instagram pic @kohsamuiguide.

P.S. You can find every tip for discovering Thailand's plants and animals in the archive, or subscribe by email and get all the details straight to your inbox. Enjoy!

Sources: A, B, C