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.

On a dinosaur hunt

As our boat made its way down a tidal creek in Bhitarkanika, we spotted a monitor lizard on the mud bank and halted. The meter long lizard was well aware of our presence, but did not judge us to be a threat. As it made its slow way along the bank, I asked Amar whether he had ever seen it move faster. He said that he had seen it run. I later found that it can crank up its speed to a little over Usain Bolt’s!

The monitor lizard can be spotted in various parts of India, but the only previous photos I had were in zoos. I was happy to keep clicking, and even happier that I managed to get a photo of it flicking its forked tongue (featured image). This enables lizards and snakes to sample chemicals which are not volatile enough for a nose to pick up. Monitor lizard in Bhitarkanika National Park, Odisha It is believed that the forked tongue allows these animals to follow a chemical trail. One of the components of the diet of a monitor lizard is bird’s eggs. Kingfishers lay eggs in holes in the mud near a creek. Maybe this creature was trying to locate such a nest. The next day we came across a monitor lizard being harried by a flock of green bee eaters. It crept slowly across an open patch in the ground and disappeared into a bush. I couldn’t figure out whether the birds had driven it away from nests, or whether it had created a diversion while its mate raided the nest.

Popular literature and movies portray dinosaurs in the shape of these giant lizards. But monitor lizards are not the descendants of dinosaurs; they are distant cousins. In 2012 the rediscovery of a new fossil along with molecular and fossil phylogenetic studies concluded that monitor lizards arose in Asia by the late Miocene epoch, and evolved along with mammalian competitors. The dinosaurs had by then evolved into birds. In India, the Himalayas had already risen, and the monsoon had set in.

What we saw on both occasions was a lizard on a dinosaur hunt!