The Asian water monitor (Varanus salvator) is a large varanid lizard native to South and Southeast Asia.

It is an excellent swimmer and hunts fish, frogs, invertebrates, water birds, and other types of aquatic and amphibious prey.

Morphological analyses have begun to unravel this taxonomic uncertainty but molecular studies are needed to test and confirm the validity of certain groupings within this genus.

[1] The black water monitor from Thailand's Satun Province and Thai-Malaysian border area was formerly the subspecies V. s. komaini, but now is regarded as a junior synonym and melanistic population of V. s.

[7] The Asian water monitor is dark brown or blackish with yellow spots on the underside that fade gradually with age.

[12] In captivity, Asian water monitors' life expectancy has been determined to be anywhere between 11 and 25 years depending on conditions, in the wild it is considerably shorter.

[15] The Asian water monitor is widely distributed from India, Bangladesh, Sri Lanka, Myanmar and Thailand, Cambodia, Laos, Vietnam, the Chinese Guangxi and Hainan provinces, Malaysia, Singapore to the Sunda islands Sumatra, Java, Bali, Borneo and Sulawesi.

[1] The Asian water monitor is semiaquatic and opportunistic; it inhabits a variety of natural habitats though predominantly resides in primary forests and mangrove swamps.

In fact, it has been known to adapt and thrive in agricultural areas as well as cities with canal systems, such as in Sri Lanka, where they are not hunted or persecuted.

By eating this decaying flesh, the lizard provides benefits to the ecosystem by removing infectious elements, cleaning the environment.

[19] The first description of the water monitor and its behaviour in English literature was made in 1681 by Robert Knox, who observed it during his long confinement in the Kingdom of Kandy: "There is a Creature here called Kobberaguion, resembling an Alligator.

He will come and eat Carrion with the Dogs and Jackals, and will not be scared away by them, but if they come near to bark or snap at him, with his tail, which is long like a whip, he will so slash them, that they will run away and howl.

[21] Water monitors have been observed eating catfish in a fashion similar to 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.

[23] As carnivores and scavengers,[24] the diet of the Asian water monitor in an urban area in central Thailand includes fish, crabs, Malayan snail-eating turtles (Malayemys macrocephala), Chinese edible frogs (Hoplobatrachus rugulosus), birds, small rodents, domestic cats (Felis catus) and dogs (Canis familiaris), chickens (Gallus gallus domesticus), food scraps and carcass.

[28] In Sri Lanka, human corpses are often scavenged on by V. s. salvator, which can make it hard to identify the deceased, or to run autopsies.

[29] In one case however, the presence of eight dead water monitors near the corpse of a partially scavenged 51 year old man prompted investigation that revealed the possibility that the man died from poisoning after ingesting a bottle of Carbosulfan pesticide, which then poisoned the water monitors that scavenged on his body.

The aftereffects of a Varanus bite were thought to be due to oral bacteria alone, but recent studies have shown venom glands are likely to be present in the mouths of several, if not all, of the species.

[31][32] Adult water monitors have very few predators; with the exception of human hunters, only saltwater crocodiles (Crocodylus porosus) are known to target them.

[33] When feeling threatened, water monitors have been known to attack humans, and they should be handled with caution, as their teeth can inflict a severe injury.

[35] Today the majority of the harvesting of feral water monitors occurs in Southeast Asia, in Indonesia, and in peninsular Malaysia.

[40] In India, several tribal communities hunt these monitor lizards for their meat, fat and skin and the eggs are also harvested.