Asian Water Monitor Lizards in Lumpini Park

Lumpini Park's Resident Monitor Lizards

Lumpini Park has a large population of free-roaming monitor lizards, specifically the Asian water monitor (Varanus salvator), the world's second-largest lizard species. Hundreds of these semi-aquatic reptiles live freely around the park's lakes, basking on the lawns, climbing trees, and scavenging.

Monitor Lizard Fast Facts

Scientific NameVaranus salvator

Common NameAsian Water Monitor (ตัวเงินตัวทอง)

Typical Adult LengthUp to 1.5–2 meters (5 to 6.6 feet)

Maximum LengthAbout 3 meters (10 feet)

Typical Adult WeightCommonly up to about 20 kg (44 lbs)

Maximum WeightOver 50 kg (110 lbs) in large males

LifespanNot well documented in the wild; up to 15.7 years recorded in captivity

Clutch Size5 to 25 eggs (often laid in rotting logs or tree stumps)

Diet in ParkFish, turtles, birds, rodents, carrion

Legal StatusProtected (Wild Animal Conservation and Protection Act B.E. 2562 (2019))

Asian water monitor lizard basking on the grass next to the lake in Lumpini Park with Bangkok skyscrapers in the background

Varanus salvator

Monitor Lizards: Bangkok's Urban Giants

While their large size can be intimidating, the monitor lizards in Lumpini Park are shy and rarely behave aggressively unless provoked. As reptiles, they bask in the sun to warm up; in a field study in Singapore, water monitors usually left their night shelters after 10:00 and were most active in the afternoon. These skilled swimmers can stay underwater for up to 30 minutes while hunting. They also climb trees, for example to escape threats.

The Ecological Role of Monitor Lizards

As active predators and scavengers, these monitor lizards play a part in Lumpini Park's ecosystem. They eat fish, birds, turtles and rats, and scavenge animal carcasses. They help dispose of carcasses and keep the numbers of rats and aquatic animals in check.

Asian water monitor lizard swimming in a canal at Lumpini Park Bangkok

Semi-aquatic behavior

Monitor Lizard Population & Relocation

A 2016 survey by the Bangkok Metropolitan Administration (BMA) counted about 400 monitor lizards in the park. That year the BMA relocated 203 lizards to the Khao Son Wildlife Breeding Station in Ratchaburi following complaints that they were damaging trees and landscaping and that runners and cyclists were falling while swerving around them. The figure of about 400 was still cited in 2025, when the BMA said it was looking at ways, with the national parks department, to curb further growth.

Asian water monitor lizard resting near a pond in Lumpini Park

Tua Ngoen Tua Thong

Thai Culture and the Monitor Lizard (Hia)

The monitor lizard has a dual reputation in Thai culture. Its formal Thai name, 'hia' (เหี้ย), is traditionally associated with bad luck and used as a strong swear word. To combat this stigma, locals refer to them as 'tua ngoen tua thong' (silver and gold creatures). Despite the cultural superstition, the Asian water monitor is officially protected under Thailand's Wild Animal Conservation and Protection Act B.E. 2562 (2019), making it illegal to harm or kill them.

Safety guidelines

How to safely observe the lizards

Water monitors are wild animals. They are not aggressive toward humans under normal circumstances, but they will defend themselves if they feel threatened. Follow these simple rules to ensure a safe visit.

Keep your distance

Keep a safe distance and watch the lizards from afar. Do not try to touch, pet, or pose closely with them.

Do not feed them

The BMA asks visitors not to feed the lizards or any other animals in its parks. The lizards find their own food, and their natural eating habits keep the ecosystem healthy.

Never corner a lizard

Do not chase or corner a lizard, and always leave it an open escape route, especially toward the water. A cornered lizard may bite in self-defence.

Watch your step

Lizards cross the running and cycling paths, and runners and cyclists have fallen while swerving to avoid them. Stay alert, particularly around bends.

Seek medical help if bitten

Carrion stuck in a monitor lizard's teeth carries bacteria that can infect a bite wound. If bitten, wash the wound with soap and water and seek medical attention immediately.

FAQ: Monitor Lizards

Answers to common questions about Lumpini Park's monitor lizards.

Are the lizards in Lumpini Park Komodo dragons?

No. The lizards in Lumpini Park are Asian water monitors. Komodo dragons are a different species native to Indonesia. They are larger, hunt large mammals, and have venom. There are no wild Komodo dragons in Thailand.

Are water monitors dangerous or venomous?

Like other monitor lizards they have venom glands, but the venom has only a mild effect on people and is not fatal. The main concern after a bite is a bacterial infection. They are shy and avoid humans, and will only attack in self-defence if they are provoked, cornered, or handled.

What should I do if a lizard is blocking the path?

Do not try to push or scare it. Give it space and walk around it. The lizard will eventually return to the water on its own.

Is it illegal to harm the lizards?

Yes. In Thailand, the Asian water monitor is a protected species under the Wild Animal Conservation and Protection Act B.E. 2562 (2019). It is illegal to harm, capture, or kill them, and violators face fines or imprisonment.

How many monitor lizards live in Lumpini Park?

A 2016 BMA survey counted about 400 lizards, a figure still cited in 2025 reporting, and in 2025 the BMA said it was looking at ways to curb further growth. In 2016, 203 were relocated to the Khao Son Wildlife Breeding Station in Ratchaburi after officials said the population had grown too large for the park.

Where and when is the best time to spot monitor lizards in Lumpini Park?

Monitor lizards live in many parts of the park, in and around the water. They are late risers: in a field study in Singapore, water monitors usually left their night shelters after 10:00 and were most active in the afternoon, basking, resting and foraging. Late morning and afternoon are good times to look for them.

Asian Water Monitor Lizards