The shapers of jungles

Kanha is one of the most beautiful national parks. The first thing you notice are the enormous sal trees (Shorea robusta) forming patches with closed canopies. Then you notice that they are actually stands of trees in a larger grassland. The stands are carpeted with fallen leaves. The sunny grasslands are full of herds of chital (Axis axis, spotted deer). At the edges between the open grasslands and the forest are the more cautious sambar (Rusa unicolor) and barasingha (Rucervus duvaucelii, swamp deer). But if you look closer you see the species that shapes the landscape by removing litter and tilling the ground: termites. Some are visible by their mounds dotted throughout the forest, others hide in living trees and dead logs.

I spent quite a bit of time trying to figure out how high the termite mounds were. It sounds silly, but then I was in a jeep which spent three days rushing through the forest in search of tigers. Most tourists holiday in nearby resorts, and spend their times in swimming pools and air-conditioned rooms, making a couple of forays into the jungle. Of those who come to the forest, most are interested in tigers. So tigers are a boon to the locals who make their living on tourism, and their behaviour is geared to such people. A very few visitors come to the forest to see more, and the guides and jeep drivers are happy to talk to them about their own experiences. But you just cannot get off jeeps to make measurements. So I had to improvise by taking photos of termite mounds with different things to give a scale. Everything simplified when I saw two people, forest workers, walking between two mounds. That photo clearly told me that the large mounds were about two meters high. I saw the Northern plains gray langur (Semnopithecus entellus, hanuman) crouched behind a smaller mound. These langurs are about a meter tall. So that sort of verifies my estimate by eye that the larger mounds are twice as tall.

I’ve found termites (order Blattodea, infraorder Isoptera) fascinating for a while. They are cockroaches (order Blattodea) which adapted to eating wood by harbouring a microbiome of bacteria, protists, and fungi in their stomach. In fact, the study of termites gave the first clue that many animals could have flourishing ecosystems inside them, a discovery that is now increasingly used in treating human disorders like Type II diabetes. In a forest they munch up fallen logs and leaves and are important recyclers. But they bore into trees and wood, which makes them pests for us at home or in farms. This bunch of cockroaches also developed eusocial behaviour some time in the Triassic or Jurassic, becoming differentiated into castes of workers, queens, and kings. When I was young I would see yearly swarming of termites, as a queen and her retinue set off from their old palace in search of a new home. So I know that a termite is only a couple of millimeters in size. The mound is a thousand times larger. Calling it a palace is shortchanging the mound, because I know of no human queen who lives in a two-kilometer tall palace. Perhaps one should compare it to a medieval citadel, a city which houses the court and also all the industry which supports it.

I’d spent some time photographing termite mounds up close in the Bijrani range of Corbett NP. You can see from these photos that they have a contoured surface which is rather smooth. The material glitters in the sun, which makes me think that bits of minerals in the soil, or insect chitin could be incorporated into it. I found an interesting group of papers which studied the strength and engineering of these mounds in a non-destructive way. They found that two castes of termite workers continually build pellets of wet mud. Other castes of workers then cement these “bricks” into walls using liquids that they secrete from the body. The wetness of the mud allows the suspended granules of mud to settle into any cracks in the walls that need repair, and the termite-spit then makes it proof against the hard monsoon of this part of India. Another paper led me to believe that the two meter tall termite citadels could be several hundred years old.

But which termite made these mounds? I’m as sure as I can be, without a photo of a termite, that they are made by Odontotermes obesus. I wish this common forest termite in had an easier name. This is the species which builds these tall conical mounds with flutes which look like Gaudi could have dreamt them up. But I’d seen and photographed other shapes too. Not knowing enough about termites, I’d assumed that they were merely citadels in the early stages of construction. But apparently not. Very often, the shape of a mound tells you with certainty which species built it. But Chhotani, in his 45 year old gem of a paper on the termites of Kanha NP tells us of multiple species which can be found in the mounds and fungus gardens of O. obesus. And more interestingly, he describes four different shapes of mounds, all of which seem to be built by O. obesus. With this observation he speculates that when there are more detailed studies one would find that what we call a single species now will be resolved into multiple species, each one building a mound of a given shape. Unfortunately, the study of termites in India is in its infancy. Even a paper from five years ago, which claims that there are 286 species of termites in India, making up 10% of the world’s termite biodiversity, added six new species. I was not surprised that no one has performed a gene profile of O. obesus from Kanha to check Chhotani’s conjecture. So we don’t yet know whether we can really tell the species of a termite from the shape of its mound. There are so many angles to termite life, so many loose ends in their story, that one really has to look at several pictures to piece them into one view of these shapers of jungle landscapes.

Serene Saturday

Sometime the jungle is peaceful and quiet. The trail broke out from thickets into an open meadow. It was early morning. A golden sun. A small herd of chital (Axis axis, also called spotted deer) grazed in front of us. A sambar (Rusa unicolor) walked through the herd. Chital are easily spooked, but this herd did not mind us. Sambars are alert. It looked up at us briefly and went back to breakfast.

The scene before me was a very clear illustration of how these two species of deer manage to live in the same forest without conflict. The chital is largely a grazer, the sambar a browser. The chital is an under-rated ecosystem engineer. Its grazing keeps small plants from growing too high and smothering jungle seedlings before they can reach their full growth. They also keep the spaces under trees clear. A jungle looks very different from a garden gone wild because of these grazers.

This difference between the two kinds of deer is also reflected in their sizes. The small chital cannot possibly reach the lower canopy. I waited for the sambar to flick out its long tongue, as it does when it wants to reach a leaf too high even for its long neck. But this canopy hung low enough that it could just use its lips.

The little group fed peacefully. No smell or sound of a predator bothered them that morning. On a stump nearby I saw a black drongo (Dicrurus macrocercus). It is as dark as a crow, as intelligent and aggressive, and an incredibly good mimic. It is hard to get a good photo of a drongo because of its colour. I was lucky here. It sat in full sunlight for this portrait before it rushed off to its next appointment.

Living together

On the road again, we entered the lower Himalayas through Rishikesh. At an altitude of 340 meters above sea level, this is a town which is as well known as the doorway to the Garhwal Himalayas, as for its ashrams on the banks of the Ganga. We checked in to our hotel overlooking the river, and I had to scramble immediately to unpack my camera. Two sambar deer (Rusa unicolor) had come down from the slopes of the Rajaji national park on the opposite bank to water.

It is not unusual to find birds cleaning up large herbivores, but this was the first time I saw crows tending to sambar. The birds included large number of house crows (Corvus splendens), which can be told by the lighter colour of the feathers on the neck and breast, compared to the deep glossy black of the rest of the plumage. But scattered among them you can also see a darker bird with a stout and curved bill. This is the Indian jungle crow (Corvus culminatus). There has been a little rearrangement of this complex, with three species split off from what used to be one, but more of that later. I need not have hurried to unpack my camera; the sambar took their time being groomed by this murder of crows. Eventually, as the light faded, they waded off through the shallow water, up the little slope behind them, and were quickly lost in the gloom of the forest behind. A good start to our trip, I thought.

Aggression

In the sambar deer, dominant stags fight with others to retain control of hinds. The losing stags are pushed out of the herd. The IUCN red list says that sambar are vulnerable due to habitat loss across its full range. This includes southern China, south-east Asia and India. However, it is possible that there is a cryptic difference between the Indian population and the rest, which could split this in future into two species. If so, then the reasonably well-managed Indian national parks could convert the western population into the "near threatened" category, and the Chinese and south-east Asian population could then be plausibly classified as endangered. Since sambar is the main prey of tigers, it is impossible to stabilize tiger populations without first creating conditions for sambar to multiply.

In my lifetime sambar has become almost invisible outside of national parks. We saw few herds of sambar inside Pench national park this time around. I had only a couple of glimpses of a stag the fully developed antlers you expect to see this late in spring. We saw one defeated male grazing by itself in the shade under some trees. If you look carefully at the featured photo you’ll see that it has only one of the antlers. The other was broken off near the base.

Observations over many years reveal that the sex-ratio in sambar is heavily tilted towards femles. I also remember seeing, a few years ago, a sambar female in the wild who was so old that she was slightly arthritic, and her coat was greying. I’ve never seen a stag that old. Is it that stags are more vulnerable to predation? Or could it be that aggression within the species is such a source of stress that it kills off males. Looking at the male with one antler, we could not dismiss this possibility.

Later, at a waterhole, waiting for tigers to emerge, I overheard a conversation in a nearby jeep. One man said he had seen 45 tigers. A companion replied that he had seen only 25, but then, he started recently. A third chipped in to say that he writes down details of every sighting, and that he thinks he must have detailed entries on about 30. The Family nudged me to draw my attention to this bit of male aggression in Homo Sapiens. We are so lucky; I cannot imagine that stress at not seeing tigers in the wild can kill us.

Alarums and excursions

If you spend a day in one of the Project Tiger national parks, you may or may not see a tiger, but the one thing that you will learn about are alarm calls. Tourists like us move along designated tracks on a jeep inside the forest. Tigers seldom cross these paths. So the best way to find out whether a tiger is nearby is to listen to the jungle.

Of the three animals which issue alarm calls, the spotted deer Cheetal (Axis axis) and the gray langur (Semnopithecus entellus) can be seen in the photo above, and the sambar deer (Rusa unicolor) is in the featured photo. The cheetal thrive in Pench National Park. They are easily spooked. Sometimes you see a herd grazing near a track, looking up at you warily as you pass. But very often you see them already running. A naturalist once told me that this is a good sign, because it shows that they are not habituated to humans. Cheetal alarm calls are the first thing you hear when a leopard or tiger is sighted. They may soon be followed by the alarm call of langurs. Usually, when you hear this, your guide will drop everything else and rush towards the sound. Since the calls carry easily in the jungle, you will find that there are several jeeps which arrive at the source of the calls.

Tiger spotting requires patience and persistence. Sometimes the calls stop, and you do not know whether that is because the predator has stopped moving, or because it was a false alarm. The lore amongst guides is that cheetal calls could be false alarms sometimes, but the alarm call sounded by sambar deer is always correct. I saw sambar approaching water holes on two occasions. Both times they were so cautious that it was a wonder. The featured photo shows a lone sambar moving between trees at the edge of a clearing around a waterhole. It spent almost twenty minutes walking a distance of about a hundred meters. The second time I saw a group coming to a large pond. There were wary groups of monkeys drinking water, taking turns to keep watch as the rest of the group drank. A couple of spotted deer were also drinking water (see photo above). They were quiveringly tense as they drank, but they walked to the water very quickly, drank, and walked away again.

The sambar are different, they took a long time to approach the water. Then after drinking, they waded into the water (photo above). Even inside the water they were extremely cautious: scanning their surroundings with every step they took. The two scouts were soon joined by others, including young. Their coats were matted, as if they were already wet. Sambar like to wade, but they were so wary that they stood in knee-deep water until the light began to fade and we were forced to leave.

From the difference in behaviour that I saw, I could believe our guide when he said that a sambar’s alarm call is always correct.

Sambar deer

The only group of Sambar deer we saw in Ranthambore was the one in the featured photo. Of the group of four, the three in front seemed to be a mother and her two young. The one in the background looks like another adult female. The group was aware of us, but they continued to feed. The female at the back occasionally lifted her front feet off the ground to reach for hanging leaves.

Although we did not see any male Sambar, they were definitely around. Every day we heard alarm calls of lone Sambar: a short bark repeated periodically. These alarm calls signify a tiger or a leopard in the neighbourhood. I learnt a bit of jungle lore from one of the guides. Apparently Sambar keep making these alarm calls as long as the tiger is on the move. When it sits down, the calls cease, but the Sambar keeps a watch and calls again when the tiger starts moving.

We tracked the movement of a predator this way once. It seemed to have been fairly close to the road when we heard the alarm call of the Sambar first, but then it gradually moved away and we lost it. The unseen predator was reluctant to move away, because it hunkered down several times before giving up and vanishing into the forest. It was probably a leopard, because we were near a leopard’s kill.