02/12/2024
India is home to four Monitor lizards – the Bengal Monitor (Varanus bengalensis), the Asian Water monitor (Varanus salvator), the Yellow monitor (Varanus flavescens) and the Desert monitor (Varanus griseus).
The Bengal monitor (Varanus bengalensis), also called the common Indian monitor, is a monitor lizard distributed widely in the Indian Subcontinent, as well as parts of Southeast Asia and West Asia. This large lizard is mainly a terrestrial animal, and its length ranges from about 61 to 175 cm (24 to 69 in) from the tip of the snout to the end of the tail. Young monitors may be more arboreal, but adults mainly hunt on the ground, preying mainly on arthropods, but also taking small terrestrial vertebrates, ground birds, eggs and fish. Although large Bengal monitors have few predators apart from humans who hunt them for meat, younger individuals are hunted by many predators.
Two subspecies of the Asian monitor can be found in India, namely the Andaman monitor, which dwells only in the Andaman islands, and the Southeast Asian water monitor (Varanus salvator macromaculatus) residing in east and north-east India, and the Nicobar islands.
The yellow monitor is a medium-sized monitor, measuring from snout to vent between 45 cm and 95 cm including the tail and weighing up to 1450 gm. It has subcorneal teeth, scarcely compressed. Its snout is short and convex, measuring a little less than the distance from the anterior border of the orbit to the anterior border of the ear; canthus rostralis distinct. Its nostril is an oblique slit, a little nearer to the end of the snout than to the orbit. The digits are short with the length of the fourth toe, measured from its articulation with the tarsus to the base of the claw, not exceeding the length of the femur. The tail of the yellow monitor is feebly compressed and keeled above. The head scales are small and subequal; the median series of supraocular scales slightly dilated transversely. The scales on upper surfaces are moderate, oval and keeled. Abdominal scales are smooth and in 65 to 75 transverse rows. Caudal scales are keeled; the caudal keel with a very low, doubly toothed crest. Adults are olive or yellowish brown above, with irregular darker markings which are generally confluent into broad cross bars; a blackish temporal streak; lower surfaces yellowish, with rather indistinct brown cross bars, which are most distinct on the throat. Young individuals are dark brown above, with yellow spots confluent into crossbars; lower surfaces yellow, with dark brown cross bars.
koniecznyi (Indian desert monitor) has three to five bands on its back, 13-19 bands on its tail, a plain tail tip, 108-139 rows of scales on its midsection, and a broader and flatter head when compared to the other subspecies. This subspecies has the smallest body of the three. Desert monitors normally display a variety of body coloration from light brown and yellow to grey. They average about one meter in length, but can reach total body lengths of almost two meters. These lizards can also have horizontal bands on either their backs or tails, along with yellow spots across their backs. Their young are normally a brightly coloured orange and have distinctive bands across their backs which may be lost as they mature. Their nostrils are slits located farther back on their snouts (closer to the eyes than the nose), and their overall body size is dependent on the available food supply, the time of year, environmental climate, and reproductive state. Males are generally larger and more robust than females. Those differences allow males to be distinguished from females. Like all lizards, they go through periods of molting in which they shed their outer layer of skin to expand their overall body size. For adults, this process can take several months and happens around three times per year. Their skin is adapted to the desert environment where they live, and they are excellent swimmers and divers and have been known to enter the water occasionally to hunt for food. They are found in barren areas of mainly sand and/or clay soils, and occasionally in wooded areas. Their diets include numerous invertebrates, small lizards and birds, bird eggs, young turtles and tortoises (and their eggs), rodents, and even cobras and vipers. They are strong diggers and can easily build burrows that are several feet long.