varanidae

Varanids are the largest lizards / saurians found in the country and in the world. Sri Lanka harbors two species of varanids, the Land monitor (Varanus bengalensis) and the Water monitor (Varanus salvator).

Varanus bengalensis is mainly found in the lowland dry zone of the country, but reaches elevations of ca. 500m. It is one of the most widely distributed of the living varanids. It inhabit a large range of habitats ranging from arid desert fringes to rainforests, but is most common in farmlands (particularly the coconut plantations) and dry, open forests. Land monitors reach a maximum snout to vent length of about 140 cm in Sri Lanka and large specimens can weigh over 10 kg. Land monitors spend the nights in burrows, where their body temperature decreases. The following morning they must raise their body temperatures by basking before commencing activity, hence they are rarely active early in the morning. Younger Land monitors frequent the vicinity of rivers, and that adults are found in drier forest, scrublands and grasslands unlike the water monitors which do not usually venture far from the water. They are excellent climbers. Even large adults can ascend vertical tree trunks with ease, and they are reported to be agile enough to stalk and capture even roosting bats. Despite their large size, these lizards get most of their nutrition from tiny prey and feed mainly on beetles, grubs, orthopterans, scorpions, snails, ants and other small invertebrates, which are consumed in enormous numbers. Hence they are important biological controllers of agricultural pests.

In contrast, the Water monitor (Varanus salvator) is one of the most widespread lizards in the country and is distributed from the coastal plains up to some parts of the third peneplain in the wet zone. Varanus salvator can attain total lengths of 3 meters, thus it is the second largest lizard in the world, second only to the Komodo dragon (Varanus comodonensis) of the Indonesian islands, which grow over 3 m. The Water Monitor is an extreme carnivore. Hence it eats a large variety of small animals that it believes it can consume. Among some of the common prey are: birds and their eggs, small mammals (especially rats), fish, lizards, frogs, snakes, juvenile crocodiles, tortoises are turtle eggs. The primary hunting technique used by Varanus salvator, as well as by other monitors, is characterized by 'open pursuit' hunting, rather than stalking and ambushing. While hunting for aquatic prey, Varanus salvator can remain submerged for up to 30 minutes. Varanus salvator is semi-aquatic and has a wide range of habitats. They are frequently seen on river banks and in swamps. But it also inhabits anthropogenic habitats such as ditches in towns etc.

Being the first Sri Lankan reptile to receive legal protection since 1937, the Water monitor is not killed for food due to the belief that it’s flesh is highly poisonous. But the Land monitor is widely killed in the country, for food and for its skin. It is listed as a ‘Commercially threatened’ taxon in the IUCN and also in the Appendix 1 in the 1992 list of CITES (Convention on the International Trade of Endangered Species). Both monitors are predators of agricultural pests and are efficient scavengers in the environment.

Genus Varanus Gray, 1827

Varanus bengalensis (Daudin, 1802) ; Land Monitor (E) ; Thalagoya (S)
Varanus salvator salvator (Laurenti, 1768) ; Water Monitor (E) ; Kabaragoya (S)