Monitor this (and that)

When I had my first sighting of an Indian water monitor I didn’t know how lucky I was. Only later, when I looked for other images did I realize that if I’d seen it walking or swimming I would have seen only the black and silver top. Seeing it halfway up a tree, in a hide it had selected for the night, allowed me a great view of the stripes and rosettes on both the dorsal and ventral sides. I’ve always wanted to use these technical words for upper and lower, and I have to tip my hat to the water monitor for giving me this great opportunity.

More surprises followed when I looked it up. There is no clear record of Indian water monitors. Is this the same as an Asian water monitor (Varanus salvator)? Descriptions of the normal range of V. salvator do not include Assam and north-eastern India, although it is reported from the Andaman and Nicobar islands, as well as far south-west in Sri Lanka. In any case, it is not clear whether V. salvator is one species or four. This single sighting of the brilliantly coloured monitor lizard has taken on a mysterious air in my mind.

The previous day we had a wonderful view of a common Bengal monitor (Varanus bengalensis) creeping through vegetation. I’d last seen it in a completely different habitat a year ago. Although these creatures remind us of the dinosaur pictures of pop culture, they are not. The monitor lizards probably rose in Asia during the Cretaceous period, at about the same time that birds were evolving out of the Jurassic dinosaurs. India was completely separated from Asia in this era.

The center of evolution of these lizards is south-east Asia, as one can guess from the fact that the largest monitor of all, the Komodo dragon, comes from that area. North-eastern India is a hotspot of biodiversity partly because two ancient ecosystems meet here. The monitor lizards of eastern India are examples of this ancient radiation. We live in the best of times when this meeting has produced enormous numbers of species, the worst of times because human expansion is removing these habitats rapidly. Places like Kaziranga are the last spots where you can see much of this diversity.