SHERMIN DE SILVA
We caught the gleam of his tusk against the hillside as he wove his way down toward a herd. It was not him we were interested in: we were there to learn how the females lived. We were in the midst of a very large and scattered group of elephants, on an abandoned logging road overlooking the dry reservoir bed. It was the height of the dry season in Uda Walawe National Park, Sri Lanka. “Uda Walawe” means the upper part of the Walawe river, one of the four major rivers of Sri Lanka, the damming of which resulted in its namesake protected area.
Unlike their African cousins, not all Asian elephants have tusks: most have diminutive incisors known as “tushes”. Tusks only adorn a fraction of males in any population, and in Sri Lanka this minority is thought to be as low as 3 to 5 %. This tusker bore the well-deserved name of “Raja,” meaning “King” in Sinhalese.
Always appearing in the National Park during his annual reproductive period known as musth, Raja was usually uncontested by all other males. This was my second encounter with him, and it was only my second week as a would-be elephant researcher. I had arrived full of anxious questions: Where should I work? What should I study? Would the elephants even allow me to watch them? Was it safe to do so? My advisors at Penn studied baboons in Botswana. They had no answers for me.
Winding his way casually down the hillside, he eventually arrived at our vehicle. I was accompanied by my research assistant and a tracker from the National Park. As far as I knew, no one had studied Asian elephants from a vehicle up close before, as had been done in Africa. Because Asian habitats are typically denser, observations were usually conducted from the safety of a tree. Of course this greatly limited mobility, for behavioral research I needed to be able to follow them. I had decided to follow the strategy, untested thus far in Asia, of keeping still with the engine off. But I was nervous about putting others in the vehicle with me at any risk. My assistant had gamely agreed to undertake this new style of observation, but the poor tracker was petrified and disappeared into the furthest recesses of the vehicle.
Raja drew up shoulder to shoulder with us, and peered at me for a moment that seemed to distort time. I could count every wrinkle, freckle and eyelash as his cavernous breath filled my ears. We took note of the gunshot wound on his leg, swollen and raw. A gust of wind made a plastic clasp click against metal, the spell broke, and we went our separate ways. On this day and others, Raja demonstrated many things – that a bull in musth, shot at by people, feared by many, could allow such a moment of mutual reflection meant that there was much we still had to learn. The elephants would allow us into their lives, my mind was at ease.
Thus began what would become the only continuous study of a wild Asian elephant population in the world, now ongoing for more than ten years. I spent much of this time focused on understanding who was who among the females and calves, who lead lives distinct from roving males such as Raja. From this we learned that the number of elephants making use of this relatively small protected area was about twice as high as anyone thought , and that their social worlds differed markedly from that of African elephants [2,3]. Social contact even among family members were extremely dynamic and did not follow any clear seasonal patterns [2,4].
Most surprisingly, it now appears that females don’t subscribe to linear, age-based dominance hierarchies . This overturns much of the thinking about what elephants are like, based primarily on research on African savannah elephants. I found myself increasingly intrigued by whether these differences might have an ecological basis – namely, the fact that Asian elephants, and this population in particular, live in habitats that are much more predictable as well as lacking in large non-human predators in comparison to African savannah elephants. I proposed a hypothesis termed “ecological release,” alluding to the idea that having it relatively easy in ecological terms might allow individuals to move about more freely, making hierarchies unenforceable . The idea is that sociality follows a gradient: when resources are very scarce and unpredictable, stable groups may be precluded – this is classically known as the “ecological constraints” hypothesis. At the other end, where resources are abundant and predictable, cohesive groups may be unnecessary in the absence of other benefits such as protection from predators. This is ecological release. It would appear that African savannah elephants fall in the middle of the spectrum, whereas Asian elephants fall closer to one of the ends. It is left to be seen whether other species show similar trends.
We documented some interesting rarities, such as the first known case of a dwarf elephant in the wild. We were astonished to see that our mighty little bull was more than a match for his taller competitors ! Our meticulous observations of births and deaths  also uncovered some unwelcome news: elephant populations may be struggling to keep up in the face of the insults humanity keeps throwing at them. Asian elephants are already classified as endangered, with many populations numbering in the mere hundreds and more than a few in double digits, scattered across increasingly fragmented landscapes. Being among the slowest reproducers in the animal kingdom, increases in mortality due to hunting and deteriorated habitat coupled with ever-diminishing reproductive rates may push them over a cliff from which there is no return as existing populations age. But it’s difficult to get people to take note. Demographic collapse is like carbon monoxide poisoning – difficult to detect, silent, lethal.
I had chosen to work on Asian elephants because despite more than five thousand years of serving human needs as captive animals, we still knew so little about this shy and secretive animal as it truly lived. Even as we look to the stars and ponder colonies on Mars, intelligent life on Earth is ebbing. The Asian elephants are an example, in danger of disappearing as we scratch the surface of something that it is as yet premature to call “understanding”. I was motivated to do more than merely study them. This led to the creation of Trunks & Leaves, dedicated to both the species and its habitat. When we lose biodiversity, we lose more than the species, the interactions, the as-yet-undiscovered-pharmacopeias, and the functional integrity of ecosystems on which we rely (as if that weren’t bad enough). We also lose – perhaps something that is to most non-scientists of lesser concern but to me seems rather fundamental – the very ability to understand how nature operates. Perhaps this was never for us to know.
The first question, of course, is why? Why are elephants, and so many of their neighbors, threatened?
When I began, the question sat at the distant heart of a frayed tapestry on which I was diligently working at the edges. As a behaviorist, I am trained to think in terms of proximate and ultimate causes. The proximate causes were self-evident – conflicts over land with farmers or plantations, hunting, accidents. But the ultimate causes and effects stretch out beyond the elephants, the forests, the farmers…they reach out to industries, global consumption, finance, development. The threads have slowly begun to come together over time; the picture they weave is far from simple.
Do we want to save these species? Will we ever be willing to do what it takes?
Shermin obtained her Ph.D from the University of Pennsylvania, studying the behavioral ecology and demography of Asian elephants, and directs the Udawalawe Elephant Research Project in Sri Lanka. She is currently a Postdoctoral Fellow at the Smithsonian Conservation Biology Institute. She also serves on the Asian Elephant Specialist Group of the IUCN Species Survival Commission, and on the Board of the Asia Section of the Society for Conservation Biology as Communications Officer. Previously she was a postdoctoral fellow in the College of Life Sciences at the Institute for Advanced Study in Berlin and NSF Postdoctoral Research Fellow at Colorado State University, in the Department of Fish Wildlife and Conservation Biology. She is also a founder and trustee of EFECT, Sri Lanka. When she is not thinking about planetary issues, Shermin likes to explore music and the arts and also how these could be linked to conservation messages.
1. de Silva, S., A.D.G. Ranjeewa, & D.K. Weerakoon (2011). “Demography of Asian elephants from identified individualsat Uda Walawe National Park, Sri Lanka.” Biological Conservation, 144, 1742-1752. DOI: 10.1186/1472-6785-11-17.
2. de Silva, S., & G. Wittemyer (2012). “A Comparison of Social Organization in Asian Elephants and African Savannah Elephants.” International Journal of Primatology, 33(5), 1125-1141. DOI: 10.1007/s10764-011-9564-1
3. de Silva, S., V. Schmid, G. Wittemyer (in press). “Fission-fusion processes weaken dominance networks of female Asian elephants in a productive habitat.” Behavioral Ecology.
4. de Silva, S., A. Ranjeewa, & S. Kryazhimskiy (2011). “The dynamics of social networks among female Asian elephants.” BMC Ecology, 11, 17. DOI: 10.1186/1472-6785-11-17
5. de Silva, S., U.S. Weerathunga, T.V. Pushpakumara (2014). “Morphometrics and behavior of a wild Asian elephant exhibiting disproportionate dwarfism.” BMC Research Notes 7, 933
6. de Silva, S., L. Webber, U.S. Weerathunga, T.V. Kumara, D.K. Weerakoon, G. Wittemyer (2013). “Demographic variables for wild Asian elephants using longitudinal observations.” PLoS One, 8(12): e82788. DOI:10.1371/journal.pone.0082788).