Varanus salvator macromaculatus

Sungei Buloh Wetlands

The Malayan Water Monitor or Southeast Asian Water Monitor or Asian Water Monitor is among the largest varanid lizards in the world native to South and Southeast Asia. It is one of the most common monitor lizards in Asia, ranging from coastal northeast India, Bangladesh, Sri Lanka, mainland Southeast Asia, and southern China to Indonesian islands where it lives close to water. Their coloration ranges from brown to black with orange, yellow or white spots or ocelli. Their heads are ventrally flattened with an elongated snout. Their tails are long and powerful and are used for swimming, fighting or hunting.

Seeing this lizard and being able to photograph it from close proximity is, I think, among my fondest memories of Singapore and the Sungei Buloh Wetlands..

Sungei Buloh Wetlands

The Sungei Buloh Wetlands are a wetland nature reserve in the northwest area of Singapore. It is the first wetlands reserve to be gazetted in Singapore (2002), and its global importance as a stop-over point for migratory birds was recognised by the inclusion of the reserve into the East Asian Australasian Shorebird Site Network. The reserve, with an area of 130 hectares, was listed as an ASEAN Heritage Park in 2003. It is one of those natural forests that play a big part in creating an ecological balance in the region.

The site only gained prominence in 1986 when a call was made to conserve the area by members of the Singapore Branch of the Malayan Nature Society. Particularly significant was its unusually high variety of bird species, which included migratory birds from as far as Siberia on their way to winter in Australia. Their suggestion was taken up by the government, and a site with an area of 0.87 km² was given nature park status in 1989. The Parks & Recreation Department, a precursor to today's National Parks Board, developed and managed the nature park with a team of experts. The most notable names from the team included the Wildfowl & Wetlands Trust from the United Kingdom and World Wide Fund for Nature. Sungei Buloh Wetland Reserve, then known as Sungei Buloh Nature Park, was officially opened on 6 December 1993 by then Prime Minister Goh Chok Tong.

Among the many birds that can be spotted feeding on the diverse fauna variety of worms and molluscs, are the Eurasian whimbrel, common greenshank, common redshank, Mongolian plover, curlew sandpiper, marsh sandpiper and the Pacific golden plover, the yellow and the cinnamon bitterns. There is a resident family of smooth otters as well as the rare lesser whistling-duck, and the rare milky stork. The reserve forms part of the Kranji-Mandai Important Bird Area (IBA), identified as such by BirdLife International because it supports Chinese egrets, greater spotted eagles and greater crested terns. Atlas moth, the largest species of moth in Southeast Asia can be found in the back mangrove.

Observation hides are available where visitors can observe the flora and fauna in the surroundings in tranquility and at a distance from the animals and birds. Saltwater crocodiles (Crocodylus porosus) are occasionally seen in the reserve, although it is not known whether or not these are individuals that had wandered over from Malaysia/ Indonesia or a remnant localised population. (This species was once common in Singapore but was said to be extinct.). It is one of the four nature reserves to be gazetted in Singapore.

Malayan/ Southeast Asian Water Monitor

This large lizard is commonly seen on many shores across Southeast Asia, including the offshore islands. They are found in forests, mangroves, scrubland and beaches where they tend to stay close to water as well as in large canals in built up areas. Although mainly terrestrial, these lizards can climb trees and are also great swimmers keeping their limbs to the sides of their body, and propelling itself with sinuous undulations of the flattened tail. They can even dive underwater.

They have a black temporal band edged with yellow that extends back from each eye. Their neck is very long with an elongated snout, flat tail with a dorsal ridge and dark brown or blackish, with yellow spots on the underpart. The yellow markings on the species tend to diminish as the individual becomes older. It is listed as Least Concern on the IUCN Red List. It was described by Laurenti in 1768 and is among the largest squamates in the world.

The generic name Varanus is derived from the Arabic waral, which translates as "monitor". The specific name is the Latin word for "saviour", denoting a possible religious connotation. The water monitor is occasionally confused with the crocodile monitor (V. salvadorii) because of their similar scientific names.

Some common names for the species are Malayan water monitor, common water monitor, two-banded monitor, rice lizard, ring lizard, plain lizard, no-mark lizard and water monitor etc.

This common species occurs throughout Southeast Asia in virtually all habitats including urban areas where it may sometimes be seen feasting on roadkill. It is particularly common, however, in mangrove areas as it is a strong swimmer and it can flourish on a diet of crabs and other large invertebrates. 

It can remain submerged underwater for a considerable time. It is also an agile climber, and a raider of bird's nests. The Malayan Water Monitor is distinguished from other monitors by the position of the nostrils, which lie near the tip of the snout.

Stellio salvator was the scientific name used by Josephus Nicolaus Laurenti in 1768 for a water monitor specimen. The family Varanidae contains nearly 80 species of monitor lizards, all of which belong to the genus Varanus. There is a significant amount of taxonomic uncertainty within this species complex. 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. Research initiatives such as these are very important to assess changes in conservation assessments.

• V. s. salvator is the nominate subspecies and is now restricted to Sri Lanka, where it is known as the kabaragoya in Sinhala and kalawathan in Tamil.

• V. s. andamanensis, the Andaman Islands water monitor, inhabits the Andaman Islands and the Southern Nicobar Islands.; the type locality is Port Blair.

• V. s. bivittatus (Mertens 1959), the two-striped water monitor, is common to Java, Bali, Lombok, Sumbawa, Flores, Alor, Wetar, and some neighbouring islands within the Sunda archipelago in Indonesia; the type locality is Java.

• V. s. macromaculatus, the Southeast Asian water monitor, is found in mainland Southeast Asia, Singapore, Sumatra, Borneo, and smaller associated offshore islands. The type specimen was captured in Thailand.

• V. s. ziegleri, Ziegler's water monitor, is from Obi Island.

Varanus cumingi, Varanus marmoratus, and Varanus nuchalis were classified as subspecies until 2007, when they were elevated to full species.

The black water monitor from Thailand (type locality: Amphoe La-ngu, Satun Province and Thai-Malaysian border area was formerly the subspecies V. s. komaini, but now is regarded as a junior synonym and melanisticpopulation of V. s. macromaculatus.

Water monitors defend themselves using their tails, claws, and jaws. They are excellent swimmers, using the raised fin on their tails to steer through water. When encountering smaller prey items, the water monitor will subdue it in its jaws and proceed to violently thrash its neck, destroying the prey’s organs and spine which leaves it dead or incapacitated. The lizard will then proceed to swallow it whole.

In dominantly aquatic habitats their semiaquatic behavior is considered to provide a measure of safety from predators. Paired with their generalist diet, this is thought to contribute to their ecological plasticity. When hunted by predators such as the king cobra (Ophiophagus hannah) they will climb trees using their powerful legs and claws. If this evasion is not enough to escape danger, they have also been known to jump from trees into streams for safety, a tactic similar to that of the green iguana (Iguana iguana).

Like the Komodo dragon, the water monitor will often eat carrion. They have a keen sense of smell and can smell a carcass from far away. They are known to feed on dead human bodies. While on the one hand their presence can be helpful in locating a missing person in forensic investigations, on the other hand they can inflict further injuries to the corpse, complicating ascertainment of the cause of death.

Monitor lizards are traded globally and are the most common type of lizard to be exported from Southeast Asia, with 8.1 million exported between 1998 and 2007 for the international leather market. The Asian water monitor is one of the most exploited varanids; its skin is used for fashion accessories such as shoes, belts and handbags which are shipped globally, with as many as 1.5 million skins traded annually. Other uses include a perceived remedy for skin ailments and eczema, novelty food in Indonesia, and a perceived aphrodisiac, and as pets. In India, several tribal communities hunt these monitor lizards for their meat, fat and skin and the eggs are also harvested. They are often considered as pests and their populations are also threatened by habitat loss and habitat fragmentation.

In Nepal, it is a protected species under the Wild Animals Protection Act of 2002. In Hong Kong, it is a protected species under Wild Animals Protection Ordinance Cap 170. In Malaysia, this species is one of the most common wild animals, with numbers comparable to the population of macaques there. Although many fall victim to humans via roadkill and animal cruelty, they still thrive in most states of Malaysia, especially in the shrubs of the east coast states such as Pahang and Terengganu. In Thailand, all monitor lizards are protected species. It is still common in large urban areas in Thailand and is frequently seen in Bangkok's canals and parks. Because of this, it is currently listed as Least Concern in the IUCN Red List. These classifications have been made on the basis that this species maintains a geographically wide distribution, can be found in a variety of habitats, adapts to habitats disturbed by humans, and is abundant in portions of its range despite large levels of harvesting.

Loss of habitat and hunting has exterminated water monitors from most of mainland India. In other areas they survive despite being hunted, due in part to the fact that larger ones, including large females that breed large numbers of eggs, have tough skins that are not desirable.

In Sri Lanka, it is protected by local people who value its predation of "crabs that would otherwise undermine the banks of rice fields". It is also protected as it eats venomous snakes.

The species is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) meaning international trade (import/export) in specimens (including parts and derivatives) is regulated.

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