In August 2013, before I started this blog, I was casting about for a way to get back into popular science writing. Sure, I was writing every now and then for Anole Annals, but as much as I love lizards, there were other things I felt like writing about. The perfect impetus came in the form of an announcement for the M. Krishnan Memorial Nature Writing Award, an essay competition sponsored by the Madras Naturalists’ Society. Here’s a description of the competition:
India is home to a great variety of wild animals. The creatures found in the Subcontinent and the surrounding waters range from mammals to worms, from mighty elephants and whales to tiny arthropods. Each of these animals is fascinating in its own right, leading its unique life. It is all too easy for humans dwelling in cities and towns to be oblivious to the existence of the diversity of creatures in the land. But present they are, these living things, in forests, grasslands, marshes, deserts, scrub, agricultural land and even urban settings. Unfortunately, most of them are being adversely affected by human activities. M. Krishnan excelled at describing these animals, bringing them to the public attention. His superbly crafted writings described his observations, provided information from his deep knowledge and entertained. They created empathy for all things living.
The M. Krishnan Nature Writing Competition 2014 wishes to encourage young people from all parts of India to write on the wildlife of India. The works should, in the spirit of M. Krishnan’s writings, aim to provide a scientifically accurate account that promotes understanding of nature and support for conservation among lay persons.
Here’s my entry to this competition. It looks back at my research experiences in India (somewhat frighteningly, they span almost ten years!), all of which have been centred around some very common animals. I use these experiences to make the case that any creature can be interesting if you remember to ask “why?”
I really enjoyed writing this piece, and I’m glad that the judges liked it too! Thanks to my parents, Revathi and Vasant Kamath, and to Ramya Swayamprakash, for editing the piece 🙂 I’ll link to the Madras Naturalists’ Society version (and remove this one) as soon as they put it up.
In praise of the ubiquitous: what I have learnt from common animals
For the first fifteen of my twenty-five years, I took nature for granted. Somehow believing that nature could only be found in far-away lands filled with lions and antelope, like those I saw on television, I spent my childhood in more readily accessible imagined worlds, first those of novels and later those of science and mathematics textbooks. But this path through the imagination led me to the natural, by way of the sciences of ecology and evolutionary biology. After fifteen years of just seeing nature, I finally began to look at it with the eyes and mind of a budding biologist.
Why is science enthralling? I find that the power of science lies in its ability to lend order to seeming disorder, to find the common threads of processes that generate the overwhelmingly varied and beautiful patterns of nature. I needed this lens of order through which to view nature before I could truly appreciate it. But once you start seeing wonder in the natural world—in the complex organization of ants travelling in lines, in the skilful stalking of insects by a house gecko, in the careful progression of a seedling towards the sun—it is impossible to stop! Every plant, animal, fungus, or microbe has been shaped by the same set of ecological and evolutionary processes, and the question, “why does this organism live (or look or behave) in this way?” is always warranted.
I have spent the last decade looking at some of the commonest creatures around me and asking “why?” In this essay, I am going to share with you some of what I have learnt. If you already find all of nature interesting, I hope you will nod in agreement with me, and perhaps learn something new about the creatures I find captivating. If you think that nature is only found “out there,” in the forests and oceans far from your daily life, I hope to show you that any living organism can inspire excitement about the natural world.
My first experience looking at a common creature from a scientist’s perspective came when I began tagging along with a field biologist who studied crows. That’s right—crows. I had previously never stopped to give crows a second thought. However, it turns out that their behavioural repertoire includes an incredibly interesting interaction with koels. Like many other cuckoos, koels are brood parasites, laying their eggs in other birds’ nest and eschewing the burdens of parental responsibility. Unlike most cuckoos, however, baby koels do not harm their nest mates at all—they neither roll out eggs nor attack the crow chicks with whom they cohabit. The reasons in favour of koel chicks eliminating their crow nest mates are clear, as the surviving interloper will benefit from the crow parents’ undivided attention. So the question here is “why not?” Why do koels live harmoniously with crow chicks, instead of usurping the crow parents’ care completely? In assisting the field biologist who was answering this question by means of some clever experiments, I spent most of my time carrying ladders, painting the legs of crow chicks with non-toxic paint, and watching, by means of a little CCTV camera installed in the nests, a tiny koel chick opening its bright red mouth as wide as possible, shamelessly begging its crow parents for food. I also began to observe the methods by which science can ask why nature works the way it does.
I soon had a chance to try out my own experiments, designed to understand the behaviour of one of the world’s most unassuming animals—the antlion larva. Have you ever noticed small, conical pits in the ground, often in sandy soil along walls, sheltered by trees or eaves? Have you ever thought about what might be inside these pits? Like many children that play outside, I knew that whatever lived in these pits devoured ants—my brother had shown me how to catch ants to drop into these pits. I would then watch gleefully as powerful jaws appeared, seemingly from nowhere, to grab hold of the ant and drag it below ground. This small, conical pit became the scene of a vicious battle, with one participant, the antlion larva, unwilling to stick more than its head and jaws into the battlefield.
I had never bothered to find out what the rest of an antlion looks like, because I had not previously seen much point to antlions. But, eventually, I did dig some up. Looked at with the eyes of a scientist, these small, furry, sand-covered, almond-shaped insects led to so many questions! Antlions are quintessential “sit-and-wait” predators. Sitting at the bottom of pits they build in the sand, they wait for ants and other insects to fall in. Immediately, they snap their disproportionately enormous jaws shut and inject digestive juices into their prey. If the prey tries to escape, they flick their heads violently to hurl sand towards it, causing it to slip back into the antlion’s grasp.
Think about this strategy for a few seconds. Antlions cannot eat until an insect happens to fall into their pit, and can do nothing about one that passes just millimetres away! Imagine sitting in your kitchen for most of your life, eating only when food happens to appear within arm’s reach. Surely, you’d do well to position yourself close to the fridge?
So how do antlions decide where to build their pits? Are physical factors, such as soil, light, and moisture, important? Does the presence of other antlions affect where an individual decides to build its pit? What about the presence of ants? I attempted to answer some of these questions through “choice tests,” which involve presenting an individual with a choice and noting what it chooses. This meant creating two different environments for the antlions within a single plastic box—the choices included fine vs. coarse sand, sheltered vs. unsheltered areas, leaf-litter vs. no leaf-litter, and ants vs. no ants. I would then carefully dig antlion larvae out of their pits with a spoon, place them between the two environments, and wait for them to choose an environment in which to build their pit. Most of my results were pretty intuitive—of course antlions would rather build their pits in fine sand, unencumbered by leaf litter or moisture, but preferring the protection of shelter and maintaining a reasonable distance from other antlion pits. (Whether antlions can detect the presence of ants, via their chemical scents, remains a mystery; my first experiments suggested that they could, but subsequent replications failed to confirm this result. I’ll get back to it someday!).
Why is it obvious that an antlion, or koels, or any creature for that matter, will behave “sensibly”? The answer lies at the centre of all biology: the principle of evolution by natural selection. Natural selection has three components: organisms vary in what they look like and how they behave, these variations are passed on from parent to offspring, and certain variants are better at surviving or reproducing than others. In conjunction, these three conditions are sufficient for the spread of characteristics that help an organism survive or reproduce—our intuitive definition of “sensible” behaviour. Returning to antlions, one can now hypothesize about why, for instance, antlions most often build their pits in fine sand instead of coarse sand. Fine sand is easier to dislodge, meaning an antlion will be able to spend less time and energy digging in fine sand than in coarse sand. Energy saved while digging can be used another time, perhaps to live a bit longer, grow a bit bigger, or have a few more offspring. And time saved while digging is less time spent above ground, less time to be spotted and eaten by a hungry bird, which would be an abrupt termination of survival. Isn’t this just speculation, you say? Of course it is. But it is testable speculation—we can design and run experiments to test every claim I have just made.
Natural selection can be an especially powerful framework in which to investigate the natural history of a completely unstudied species; this is important in India, a country teeming with biodiversity that we know absolutely nothing about. On a trip to the Western Ghats, one of the world’s most valuable biodiversity hotspots and a particular haven for frogs of all shapes and sizes, I was shocked to discover that we know almost nothing about the biology of one of the region’s most common frogs. When evening fell in the monsoon season, the voice of the golden frog came to dominate the sounds we heard, as males collected in ponds and puddles to sing in choruses that attracted female golden frogs from near and far. Just like the female frogs, I couldn’t help but investigate the source of this sound that fought to outdo the ceaseless clatter of rain.
On spotting some frogs in the large, empty paddy fields in front of our dormitory, I saw that “golden” is something of a misnomer. In fact, these frogs vary in colour from golden to a dark muddy brown, an observation I found quite intriguing. It had now been seven years since I had begun taking nature seriously, and my first instinct was to ask “why?” Why do these frogs vary in colour? Do frogs of different colours behave differently? We had no information about these frogs on which to base any reasoning, so we decided to take the principles of natural selection as our basis. We collected data on male frogs’ calling rates, colour, and size in two different habitats, and then asked “how are these different attributes of male golden frogs and their habitat related to each other? How can we think about these relationships in the context of natural selection?”
Our route into understanding golden frogs was through the theory of male mating strategies. The most conspicuous male mating strategy is that of attracting females and defending territories from other males by means of a loud, colourful, or aggressive display. The most exciting animal behaviours and morphologies can be traced to males trying to attract females—the peacock’s tail, the koel’s song, the blackbuck’s horns, and the golden frog’s incessant croaking. But males of many species also adopt more covert strategies for mating with females—smaller, inconspicuous males hang out near larger conspicuous males, hoping to avoid the attention and wrath of the conspicuous male while sneaking a mating with females who have been attracted to the conspicuous male. Alternative reproductive strategies can be found in species ranging from tiny dung beetles to fearsome octopi, so it wouldn’t be surprising if some male golden frogs also adopted such strategies.
Science proceeds in fits and starts, sometimes proving hypotheses but often eliminating possibilities instead. In the case of the golden frogs, our data couldn’t tell us definitively how golden frogs behave, but did tell us how golden frogs do not behave. We initially thought that darker individuals of the golden frog might be sneaker males. If this were true, we would expect that the darker males would be smaller and would call less frequently than the more golden males.
It turns out this is not the case at all—some dark frogs are big and some call frequently. The reproductive strategies of golden frogs do not fit into the common mould adopted by many other animals, and therefore might be much more exciting! Our results suggest complex interactions between a male golden frog’s size, location, and conspicuousness. We’re in the process of publishing these results, where we make predictions about how natural selection might shape this frog’s reproductive strategies. We hope that future studies will test these predictions, establishing them as right or wrong but either way revealing much more about this common Western Ghats frog.
My surprise at learning that golden frogs are unstudied paled in comparison to my shock at how little we know about the fan-throated lizard. Unlike golden frogs, which are restricted to the Western Ghats and Sri Lanka, fan-throated lizards are found throughout the dry, scrubby environments of South Asia. Have you travelled in Madhya Pradesh, Gujarat, Maharashtra, Tamil Nadu, Andhra Pradesh, or Karnataka, driven past fallow fields or grazing lands? Chances are that you’ve come within metres of a fan-throated lizard without even knowing it. If, however, you have stopped to notice these lizards, I hope you watched them for long enough to witness their characteristic display behaviour. These small, insect-eating, diurnal lizards are somewhat unremarkable, except for a fan of skin and cartilage under their throats that males can extend and retract most dramatically to communicate with other members of their species during the breeding season.
When I began researching what is known about the fan-throated lizard, I found plenty of information about the temperatures at which they can survive, the densities at which they occur, the shape and size of the nests they build, the number of eggs they lay, but only a little about their throat-fans. A remarkable fact about them, one rarely mentioned in the scientific papers, is that populations of fan-throated lizards in different parts of the country have very different fans. A total of three fan-types exist—a small, white fan-type, an intermediately sized and partially coloured fan-type, and a large, dramatically coloured fan-type. The latter, with a gigantic throat-fan of deep iridescent blue, black, and orange, will win any competition for showiness in lizards. When I first searched for these lizards, however, I was baffled at how difficult they were to find. Camouflaged completely, they poked their heads out of cracks in the dried black cotton soil, their throat-fans neatly folded away. These lizards eluded me for days before I figured out how to spot them. However, noticing the flash of a dazzling throat-fan from over fifty metres away certainly helped me find enough animals to videotape!
I’m going to give you a little while to think about what questions one might ask about fan-throated lizards, given that all you know is that these three different fan-types exist, and that fans are used for communication through displays. In the meanwhile, I’m going to go on a slight detour about the inequality in adulation that different animals receive. We humans have a strong propensity to find certain animals more charismatic than others—our national obsession with tigers, every snake-lover’s fixation on king cobras, and global hysteria over the breeding habits of pandas reveal some of these rather irrational fascinations. Studying fan-throated lizards, I quickly learnt that colour contributes strongly to these obsessions. Everyone who saw pictures or videos of the lizards ooh-ed and aah-ed over the coloured fan-type, completely ignoring the more quirky display behaviour of the white fan-type! I was dismayed, as I had enjoyed working with the white fan-type much more—they were easier to catch, didn’t bite as hard, and were more entertaining to watch than the coloured-fan type. From my annoyance, however, arose two realizations. First, I realised that, just like with people, animals that seem easy to ignore can become much more charming when we get to know them—when we actually watch them behave, handle them carefully, and look at them closely. Conversely, animals (and people) that seem charismatic in photos might lose a bit of their appeal when we see how mean-tempered they might be. Second, I realised that, regardless of the fascination I or anyone else might have for the individual types of fan-throated lizards, they are substantially more exciting when considered together. Recognizing that the three fan types are very closely related to each other opens up questions about how these lizards and their communication systems have evolved, questions that transcend the visual beauty of any of the three types.
So, what questions would you like to ask about fan-throated lizards? Here’s one that I’ve been thinking about for the last two years: how does the display behaviour of each fan-type relate to what the fan looks like? Put another way, if you are communicating with different tools (i.e. a small, white fan vs. a large, colourful fan), do you communicate differently? The analogies to human communication are numerous—if you are bilingual, do you find your style of communication, or even your personality, different in different languages? If you are a classical dancer, do you find that meaning is conveyed through movement differently in different dance styles? I’m still in the process of doing this research, but my preliminary results do suggest that the white-fan and coloured-fan types in fact communicate quite differently! As I’m writing this, I’m three days away from a trip to watch lizards in populations of the intermediate-fan type. I can’t wait to see what their display behaviour will reveal about the evolution of communication in fan-throated lizards, to see whether some of our familiar experiences with communicating—an ability I sometimes think of as intrinsically human—is paralleled by these small, seemingly unremarkable lizards.
My 9th std. environmental science textbook listed a number of reasons why we should bother about biodiversity. I found the last reason most intriguing—almost as an afterthought, the textbook mentioned saving biodiversity for “aesthetic reasons.” I now realize that “aesthetic” was shorthand for that feeling of complete curiosity that we can feel when looking at every organism, our ability to learn something new from every piece of nature we come across, be it in the remotest jungles, the deepest oceans, or on the side of the roads we walk on every day. My most meaningful natural interactions have been with the commonest of animals, and like so many biologists, I remain enthralled enough by nature to want to spend a lifetime learning from these interactions. So whether you’ve always been captivated by nature or, like me ten years ago, hadn’t paid too much attention to the creatures around you, I urge you to look around, find a plant, animal, fungus, or microbe, and ask, “why…?”