Asian Water Monitor Fact File
The Asian water monitor is a large species of water monitor. Their long body is covered with dark brown or black scales. On their underside there may be yellow spots. These spots fade as the lizard ages. Running back across the head from the eye is a black band with a yellow edge.
As a monitor lizard they have a large forked tongue which can be used to sense prey. Monitors are the only lizards to have a forked tongue. This trait is shared with snakes. This is flicked out of the mouth to gather scents. This tongue is colored blue.
Their nostrils are positioned near the tip of the snout which is uncommon in monitors.
They have a long tail which may compromise over half their body length. The tail is flattened with a dorsal keel to assist with swimming. While swimming the tail is used as a rudder. It is also used for defense.
Some specimens of the Asian water monitor have been recorded at lengths exceeding 3m (9.8ft) though 1.5m (4.9ft) is considered average. An average monitor may weigh up to 25kg (55lbs) though again larger specimens are possible.
Food is swallowed whole. To allow additional room to achieve this they can dislocate the thyroid bone.
Their range extends across much of South-East Asia. They can be found in the following countries: Bangladesh, Cambodia, China, Hong Kong; India, Indonesia, Lao People's Democratic Republic, Malaysia, Myanmar, Singapore, Sri Lanka, Thailand and Viet Nam.
They make their home across a wide range of habitats including mangroves, swamps, wetlands, forest and shrubland.
As they have proven tolerant of human expansion they can often be found in canals, cities and agricultural areas.
Breeding takes place from April to October.
Following a successful mating the female will lay up to 50 eggs. These are laid alongside rotting logs and stumps.
The eggs incubate for 5-6 months before hatching.
Sexual maturity is tied to size but is typically reached around 2 years old. Males mature at 1m (3.3ft) long while female are mature at 0.5m (1.64ft).
Due to their powerful leg muscles they are quick runners and able to chase down prey at high speeds.
Males create a home territory. This is fiercely defended and they will attack other males who enter their area often leaving large wounds on their opponent.
These semi-aquatic animals spend much of their day around water. They are able to remain fully submerged for up to 30 minutes. Asian water monitors can live in both fresh and salt water and have been seen swimming out at sea.
They are also agile climbers and can easily move through the trees.
Predators and Threats
Asian water monitors face threats from humans due to hunting for their skin. They appear resilient to hunting as large females are often not targeted.
If the Asian water monitor is being hunted by a predator they jump from tree to tree until they can get to the safety of a river.
They also fall prey to vehicle strikes and are collected for the pet trade.
Asian water monitors have a number of additional names including common water monitor, Malayan water monitor, two-banded monitor, rice lizard, ring lizard and plain lizard.
Top - Bernard DUPONT from FRANCE / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0)
Bottom - Jerzy Strzelecki / CC BY (https://creativecommons.org/licenses/by/3.0)
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