There are 73 different kinds of monitors respectively varans existing on earth. Originally monitors live in in a wide range of habitats, from deserts and savannas to the rain forests and mangrove forests of tropical countries. In Southeast Asia the most widespread kind is the water monitor (varanus salvator). This lizards can be seen quite often, particularly in urban sites in Malaysia, where they are pretty well adapted to canalization systems, living from human food remains (rubbish), other animals and scavenging. They also appear in great numbers in Bangkok's Lumpini park with it's bigger ponds and artificial waterways there. The big reptiles make a remarkable contrast to the surrounding recreation facilities there.
A juvenile water monitor, caught by local people around Krabi, south Thailand. Either they sell him to a dealer, or they will eat him and sell the skin only. The valuable skin alone makes the lizards pursued by animal hunters for reasons of trade, but being hunted for food is another main reason. Image by Asienreisender, 2010.
Since the water monitor is the second biggest kind of lizard on earth, sometimes they are confound with aligators. On the first glance, from a distance or when swimming, they indeed look similar. An average water monitor gains a size of 150cm.
The biggest lizard on earh, the Komodo dragon, who lives on a group of islands in Indonesia, reaches a size of up to three meters. But there are also recorded cases of the very common water monitor reaching a size of three meters and more, though that's very exceptional. Then they gain a weight of up to 50kg, while the more massive Komodo dragon makes it up to 70kg.
Remarkable is their long tongue which looks like a snake's one. The tongues are of the double length of their head and split up at the end. It's their most important sense organ; they mostly orientate in their surroundings by smelling.
A sketch of a water monitor, varanus salvator. All the pictures on this page show this kind of monitor.
East of the Wallace Line in the Malay Archipelago exist most of the smaller species of the generic group of monitors. That's because in Wallacea are few carnivore living, who would be a natural enemy for the lizards. The monitors there occupy themselves the niche the absense of smaller mammal carnivores left. West of the Wallace Line are living most of the bigger monitors, particularly the water monitor, who is to find in most of Southeast Asia.
Their circulation area is around the equator, in the tropes and subtropes of Asia, Africa and Australia, but not the Americas. Being day-active, they spend nighttime in self built holes, hollow trees or similar places. Their activities are seasonal - rainy season is their "good time", because they find plenty of food. While dry season they spend most of their time in hidden places, waiting for wet weather conditions.
Monitor lizards are solitairs and usually avoid meeting each other. If it comes to the presence of two or more individuals at a place, for example due to a food resource there, it might cause a comment fighting, a ritualized fight. They don't bite each other and usually none of the rivals will be harmed.
A varan eating the head of a catfish. Image by Asienreisender in Bangkok, 2010
Their diet consists of insects and smaller animals like fish, frogs, rodents, other smaller mammals and other reptiles. Some kinds also feed from fruit and other plants. Sometimes they eat bird eggs and the eggs of other lizards. With their good smelling sense they can locate underground nests of other reptiles and dig them out. Water monitors are able to catch fish in the water; sometimes they wipe them out of the water with a stroke of their tail.
Monitor lizards can swim and climb extremely well. It might be a big surprise to see one of these big animals resting high up in a tree on a branch. Water monitors are particularly well adapted to wet habitates. Some kinds can remain under water for an hour.
Probably all kinds of monitor lizards are poisonous. Their poison is not very strong and probably designed for digesting their food. But, being bitten by such a beast, the poison causes strong pain, swellings and extended bleeding. A blood poison could happen, together with other infections. Since most of them are very shy and flee humans, there is generally absolutely no danger to expect. But, if they have no opportunity to flee, they would attack, bite and also use their tail to beat.
The monitor lizard got it's name due to it's habit of standing occasionally on it's hind legs to monitor the surrounding.
Monitor Lizards swim very well and can spend longer times under water. Images by Asienreisender in Bangkok's Lumpini Park, 2010
Monitor Lizards are hunted by humans, for food and for their skin, which makes a fine leather. In Malaysia, where the mayority of the population is Muslim, there is little hunting. Muslims don't eat the beasts. Buddhists in Thailand and Cambodia therefore eat, as it seems, almost anything, including varans and snakes.
There are also a lot of road killings of lizards who get knocked over by a car when crossing a street.
The reason why they still survived lies in the fact that they are very versatile. Particularly the above mentioned fact that they can adapt to urban areas and live in sewer systems is of big advantage for their survival. Nevertheless, as such big animals their possibilities to find hideouts are limited and therefore it is a serious threat for them to be overhunted and face extinction.
Varans are generally quite intelligent animals. They can distinguish between different other individuals, e.g. humans, they have the ability to count in a limited range, they can solve problems, learn from experiences and have a good memory. They are able to generalize and to categorize appearances.
Of all the 73 species twenty are considered as endangered animals. Habitate destruction and disruption threatens them, as many, many other animals as well. The water monitor is none of them; he is a pretty good surviver.
There are certain times varans find together for reproduction. That happens at particular places, for example places where they find food. If there are more males than females, comment fights happen for the right to copulate with the female(s). After around five weeks a number of eggs which can vary largely are layed. Interestingly, many varans use termite hills as a place to deposit the eggs. They dig a hole, place the eggs in the termite hill and the termite then close the hole afterwards. The eggs now need a considerable long time until the baby lizards are hatching. That can be up to almost a year. In the meantime the eggs are pretty safe under the guardance of the termites, who themselves neither harm the eggs nor later the hatched lizards. The timing is done so that hatching time is usually at the climax of the rainy season, what means a maximum of food for the breed. In some cases the mothers go back to the termit hill after hatching time to dig the kids out again. They can feed some two weeks from the yolks.
This varan was caught by locals (see the image in the sidebar top left). It was already exhaused and suffered several injuries. No doubt, it's remaining life time was short. As to see in the images above, it was of a considerable size.
Image by Asienreisender, Krabi, 2010
The big lizards also make good pets, because they are well adaptable to humans and intelligent animals. Of course that's something for experienced pet keepers, for there remains always a certain risk keeping such big, poisonous animals. Besides, keeping a big animal always requires to provide a bigger habitate for it to live in, e.g. a garden arrangement, proper food and some time to spend with it. A pet monitor needs some time and the right effort to be tamed. An untamed one can show pretty rude manners including biting, scratching and tail whipping. A well tamed monitor therefore, it's said, can make a good pet for the right person who knows how to deal with it.