The Bengal monitor can reach with a snout-to-vent length (SVL) of and a tail of . Males are generally larger than females. Heavy individuals may weigh nearly . Young Bengal monitors are more colourful than adults. Young have a series of dark crossbars on the neck, throat and back. The belly is white, banded with dark crossbars and are spotted with grey or yellow, particularly in the eastern part of the range. On the dorsal surface of young monitors, there are a series of yellow spots with dark transverse bars connecting them. As they mature, the ground colour becomes light brown or grey, and dark spots give them a speckled appearance. Bengal monitors have external nostril openings that are slit-like and oriented near horizontal, and positions between the eye and the tip of the snout. They can be closed at will, especially to keep away debris or water. The scales of the skin are rougher in patches and on the sides, they have minute pits, especially well distributed in males. These scales with micropores have glandular structures in the underlying dermal tissue and produce a secretion which may be a pheromone-like substance. Bengal monitors have a forked tongue similar to snakes. The function is mainly sensory, and is not very involved in the transport of food down the throat. Bengal monitors have fat deposits in the tail and body that serve them in conditions when prey are not easily available. The lungs have spongy tissue unlike the sacs of other
saurians. This allows for a greater rate of gas exchange and allows a faster metabolic rate and higher activity levels. Like all monitors, they have subpleurodont teeth, meaning the teeth are fused to the inside of the jaw bones. The teeth are placed one behind another, and there are replacement teeth behind and between each functional tooth (
polyphyodont). The maxillary and dentary teeth are laterally compressed, sometimes with a slightly serrate cutting edge, while the premaxillary teeth are conical. There are 78 premaxillary teeth, 10 maxillary and 13 dentary teeth. Replacement teeth move forward and about four replacements happens each year for a tooth. The Bengal monitor has
venom glands. However, only one controversial case report of fatal renal failure as a result of envenomation is known. == Distribution and habitat ==