Asian Water Monitor Lizard | 2nd Largest Lizard in the World

The Asian water monitor (Varanus Salvator) is a large varanid lizard native to Asia and the largest of 70 species of monitors. It is one of the most common monitor lizards in East Asia, with populations ranging from coastal northeast India to Sri Lanka, mainland Southeast Asia, and Indonesian islands. The Asian monitor is prevalent in Thailand, Malaysia, Singapore to the Sulawesi, Sumatra, Bali, Borneo, Java, and Sunda Islands.

Characteristics of Asian Water Monitor Lizard

The water monitor is a large monitor lizard species. Males reach breeding maturity when they are 40 cm (16 in) long and weigh 1 kg (2.2 lb). They do, however, grow much larger throughout their lives, with males being larger than females. Adults rarely exceed 1.5–2 m (4 ft 11 in–6 ft 7 in) in length, but the largest specimen ever recorded measured 3.21 m from Sri Lanka (10.5 ft). The average mature weight of V. Salvator is 19.5 kg (43 lb).

While alive large, specimens weigh 16 to 20 kg, 80 males killed for the leather trade in Sumatra averaged only 3.42 kg (7.5 lb) and 56.6 cm (22.3 in) snout-to-vent and 142 cm (56 in) total length; 42 females averaged only 3.52 kg (7.8 lb) and 59 cm (23 in) snout-to-vent and 149.6 cm (58.9 in) total length (35 to 44 lb).

Asian Water Monitor Lizard
Asian Water Monitor Lizard

This species of monitor has speckled grey and black skin with a light brown belly and dorsal area. They are excellent burrowers where they use their long clawed feet to dig. They have long tails which they use in defense and swimming.

Etymology of the Asian Water Monitor Lizard

Varanus derives its generic name from the Arabic word waral, which means “monitor.” The specific name is derived from the Latin word for “savior,” implying a religious connotation. Because of their similar scientific names, the water monitor (V. salvadorii) is occasionally confused with the crocodile monitor (V. salvadorii).

In Thailand, the local term for a water monitor, ‘hia,’ is used as an insult for bad and evil things, including bad people. Because the word is also thought to bring bad luck, some people prefer to refer to the animals as ‘silver-and-gold’ to avoid the jinx.

The offensive connotation can be traced back to a time when more people lived in rural areas, closer to monitor lizards. Thai villagers used to live in two-story houses, with the top floor dedicated to living and the ground floor dedicated to domestic animals such as pigs, chickens, and dogs.

Habitat of Asian the Water Monitor Lizard

Asian Water Monitor Lizards can be found in India, Bangladesh, Sri Lanka, Myanmar, and Thailand, to Cambodia, Laos, Vietnam, the Chinese Guangxi and Hainan provinces, Malaysia, and Singapore, to the Sunda islands of Sumatra, Java, Bali, Borneo, and Sulawesi.

It prefers lowland freshwater and brackish wetlands. It has been observed at elevations of up to 1,800 m. (5,900 ft). The Asian water monitor is a semiaquatic, opportunistic species that can be found in a variety of natural environments, but prefers primary forests and mangrove swamps. They can often be found dwelling near fishing boats and estuaries.

Diet & Behavior of the Asian Water Monitor Lizard

Water monitors use their tails, claws, and jaws to defend themselves. They are excellent swimmers, steering through the water with the raised fin on their tails. They are carnivores that eat a variety of prey. They have been observed eating fish, frogs, rodents, birds, crabs, and snakes. They have also been observed eating turtles, young crocodiles, and crocodile eggs.

Water monitors have been observed eating catfish in a manner resembling that of a mammalian carnivore, tearing off chunks of meat with their sharp teeth while holding it with their front legs and then separating different parts of the fish for sequential consumption.

When the water monitor comes across a smaller prey item, it will subdue it in its jaws and then violently thrash its body, crushing the prey’s organs and spine, leaving it dead or incapacitated. After that, the lizard would swallow it whole.

Fish, crabs, Malayan snail-eating turtles (Malayemys macrocephala), Chinese edible frogs (Hoplobatrachus rugulosus), birds, small rodents, domestic cats (Felis catus) and dogs (Canis familiaris), food scraps, and carcass are all part of the Asian water monitor’s diet.

  • 20 water monitors caught on Redang Island, Malaysia, were found to contain human food waste in their stomachs, plus by turtle eggs, hatchlings, crabs, and lizard eggs.

Predators of the Asian Water Monitor Lizard

Adult water monitors have few natural predators; saltwater crocodiles are known to prey on them (Crocodylus porosus). King cobras are also predators. The monitor will climb a tree to try to escape and even launch itself of high branches into water. Humans in some rural areas are known to hunt them to protect livestock and poultry.

Venom of the Asian Water Monitor Lizard

The existence of venom in the genus Varanus is hotly debated. Previously, it was thought that venom was only found in Serpentes (snakes) and Heloderma (venomous lizards). The venom may be used as a defensive mechanism to ward off predators, aid in digestion, maintain oral hygiene, and possibly aid in the capture and killing of prey.

Threats to the Asian Water Monitor Lizard

Monitor lizards are traded all over the world, and they are the most common type of lizard exported from Southeast Asia, with 8.1 million exported between 1998 and 2007. The Asian water monitor is one of the most exploited varanids; its skin is used for fashion accessories such as shoes, belts, and handbags that are shipped all over the world, with up to 1.5 million skins traded annually.

  • Applications include uses in alternative medicine such as a purported cure for skin ailments and eczema, novelty food in Indonesia, and as controversial aphrodisiac treatments.
Asian Water Monitor Lizards Are Semiaquatic

Asian Water Monitor Lizards in Malaysia

This species is one of the most common wild animals in Malaysia, with numbers comparable to the macaque population. Despite the fact that many are killed by humans through roadkill and animal cruelty, they continue to thrive in most Malaysian states, particularly in the shrubs of the east coast states of Pahang and Terengganu.

Asian Water Monitor Lizards in Thailand

All monitor lizards are protected in Thailand and especially thrive in national parks such as Kaeng Krachan in Petchaburi. It is common to sight monitors near beaches, fishing ports and in fields in most areas of of Thailand.

Asian Water Monitor Lizard Dive bombed on The Phi Phi Islands

It is still common in Thailand’s large urban areas and can be seen frequently in Bangkok’s canals and parks. As a result, it is now classified as Least Concern on the IUCN Red List and in CITES Appendix 2.

The IUCN classifications are based on the fact that this species has a wide geographic range, can be found in a variety of environments, adapts to habitats that have been disrupted by humans, and is abundant in many parts of its natural range.

An Asian Water monitor Lizard at Kaeng Krachan Crossing a Road in Petchaburi, Thailand

Fantastic Facts About Asian Water Monitor Lizards

  • Monitor Lizards are often dive bombed by birds as they are constantly wary the scavenging lizards will eat their eggs or fledglings.
  • In 2021 an 1.83m/6 Foot monitor lizard walked into a local 7-11 store and climbed the shelves in Nakhon Pathom, Thailand in front of shocked shoppers.
  • Asian Water Monitor lizards sometimes practice cannibalism
  • There are over 70 different species of monitor lizards


The breeding season of the Asian Water Monitor lizard is between April and October. A dozen white eggs will often be buried in the sand where the lizard has carved a nest. She will cover the nest and allow sunlight to incubate the eggs. The eggs will take about 6-7 months to hatch.

Q & A About Asian Water Monitor Lizard

Is it possible to keep an Asian water monitor as a pet?

Asian water monitors can be a one-of-a-kind pet for an expert with a lot of time, experience, and money. These massive lizards can live for more than 15 years if properly cared for. Some species even become tame and seek human interaction. Growing to be aggressive lizards they need a large cage, and also require a large pool for swimming.

Are Asian water monitors capable of killing you?

Humans who are bitten by common water monitors may be injected with venom, which has a mild but not fatal effect and may also be exposed to infectious bacteria. The whip-like tail and sharp claws of this monitor can also be used as weapons.

How frequently do Asian water monitors need food?

Adult Asian water monitors require only 2-3 feedings per week. Canned insects, chicks, mice, ducklings, hard-boiled eggs, or chicken organ meats are some foods to give them. Because they are scavengers, it is perfectly acceptable to feed them pre-killed prey.

What sub-species are Asian water monitors in?

Asian water monitors are in the soterosaurus sub-species

What class are Asian water monitors in?

Asian water monitors are in the class of Reptilia

What family are Asian water monitors in?

Asian water monitors are in the family of Veranidae

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