A young water monitor will attempt to swallow any small animal it can, such as crustaceans, fish, insects, and small rodents. Yet as it grows larger, it predates on bigger prey using their forked tongues to detect scents, similar to snakes, resulting in its strong sense of smell. These could range from crocodile nests to snakes and also often carrion, making them scavengers, like the Komodo dragon. As adults, they are seen as a top predator but one that is not risk-free. In mangrove habitats, large carnivores, such as salt-water crocodiles, are present and definitely could attack and consume a water monitor lizard, whilst large predators in India, like king cobras, pythons, tigers, and leopards, have been known to predate upon these water monitors. Despite this, they have adapted to both attack and defend themselves from these predators to work for their own advantage and dinner.
"As a water-dependent species, it has expanded its distribution by crossing wide stretches of water"
ADAPTATIONS & BEHAVIOURS
As a carnivore, these monitor lizards have adaptations to aid in their extreme diet, and both defend and attack against predators: serrated teeth; sharp claws; a strong body with an
The Asian Water Monitor Lizard
Thailand
The Asian water monitor (Varanus salvator) is the world’s second-largest lizard, with the Indonesian Komodo dragon taking number one position. As a generalist, semi-aquatic lizard, it can occupy a diverse range of habitats near water bodies, from primary and secondary forests, riparian forests, mangroves, swamps, and human-dominated habitats. Native to South and Southeast Asia, it has the largest distribution range out of varanids from Sri Lanka to East India, Bangladesh, Myanmar, Thailand, Cambodia, Vietnam, Malaysia, parts of Indonesia, and areas in south China. As a water-dependent species, it has expanded its distribution by crossing wide stretches of water. Its average length is 1.5m, but the longest recorded length was 3.21m (10ft) in Sri Lanka, with males significantly larger than females.
DIET
The Asian water monitor is a carnivore that will attempt to consume anything it desires, resulting in a very broad diet, commonly including small mammals, fish, amphibians, birds and bird eggs, and reptiles, like lizards, tortoises, snakes, and juvenile crocodiles. Human corpses have also been dug up by these lizards, consuming their remains like the Komodo dragon has been known to do.
armoured dorsal layer, made by bony skin osteoderms which are bone deposits inside the skin; venom glands, likely as a defence mechanism or for killing prey; and a thick tail to fight off predators. When male-male competition occurs over a female, they stand on their hind legs and attempt to wrestle, getting the other onto the ground. In the process, their claws are used to rip into one another.
The main hunting behaviour used by many monitors, including the Asian water monitor, is a technique of open pursuit hunting. They have strong leg muscles meaning they can move at very fast speeds in pursuit of their prey. This differs from stalking and ambushing hunting. When in pursuit in aquatic environments, the water monitor can stay submerged for up to 30 minutes. They use their tails dorsal ridge to steer themselves through water, making them great swimmers.
However, when the water monitor becomes potential prey, it will use its strong legs to climb trees. This usually results in escaping its predator, yet in some cases, the threat is still present, and the monitor will jump from a tree branch into a stream or river for safety. This climbing tree behaviour to escape threats is similar to that of the green iguana.
REPRODUCTION
Mating occurs seasonally and in water, with the breeding season occurring from June-September. The female will then travel to higher ground a few weeks later, laying about 20 eggs either in termite mounds, burrows, other subterranean chambers or will dig an underground chamber herself. Here she closes the chamber, leaves her eggs, and will not return. Once the young hatch after 5-9 months, and have dug themselves out, they will climb up the nearest tree branch for safety. Young water monitors are more arboreal than adults, remaining in a tree for up to a year, only leaving it to hunt prey.
THREATS
Throughout its range, the Asian water monitor lizard is quite common, yet in countries like India, habitat loss and hunting for their meat and skin have resulted in a reduced abundance of these incredible lizards, almost exterminating them from mainland India. Threats are introduced even when water monitors are inside their egg, with multiple issues potentially arising, from predation to fungus to flooding of the nest chamber.
In Thailand, all monitor lizard species are protected under the Wildlife Preservation and Protection act 1992, despite being listed as 'Least Concern' by IUCN Red List of Threatened Species. In Malaysia, they are almost as common as the number of macaques, despite many being victims of animal cruelty or roadkill. However, they are very abundant in east-coast states, like Pahang.