Research & Publications

Photo by Hamish John Appleby

The Udawalawe Elephant Research Project is a long-term study of social behavior, vocal communication, and demography of Asian elephants. This research is ongoing since 2006, and is unique for Asian elephants. Now there are close to 600 individually-identified animals that we know and recognize. We want to relate ecology – that is, the conditions of the environment elephants live in – to the way they form groups and communicate with one another. We also track births, deaths and other demographic variables to monitor population dynamics. Our goal is to understand the basic biology of Asian elephants and facilitate informed conservation & management decisions.

The Coexistence Project is a complementary research and community-based conservation initiative to understand how people and elephants share the land, as well as means to foster peaceful coexistence. It includes a social-science research component to document socioeconomic conditions, attitudes, perceptions and aspirations. It also includes ecological research using camera traps to study space-use and the effectiveness of conflict mitigation or conservation interventions.


de Silva, S., P. Leimgruber (2019). “Demographic tipping points as early indicators of vulnerability for slow-breeding megafaunal populations.” Frontiers in Ecology & Evolution, 7, 171. doi: 10.3389/fevo.2019.00171 [Full text + PDF] [Blog]

King, L., M. Pardo, S. Weerathunga, T.V. Kumara, N. Jayasena, J. Soltis, S. de Silva (2018). “Wild Sri Lankan elephants retreat from the sound of disturbed Asian honey bees.” Current Biology, 28:2, R64-R65. doi: 10.1016/j.cub.2017.12.018 [Full text] [PDF] [Press]

Karenina, K., Giljov, A., de Silva, S., & Malashichev, Y. (2018). Social lateralization in wild Asian elephants: visual preferences of mothers and offspring. Behavioral Ecology and Sociobiology72:2, 21. [Full text]

de Silva S., V. Schmid, and G. Wittemyer (2017). “Fission–fusion processes weaken dominance networks of female Asian elephants in a productive habitat.” Behavioral Ecology, 28:1, 243-252. doi:10.1093/beheco/arw153 [Full text] [PDF] [Blog] [Press]

de Silva S., U.S. Weerathunga, T.V. Pushpakumara (2014). “Morphometrics of a wild Asian elephant exhibiting disproportionate dwarfism.” BMC Research Notes. 7:933. DOI: 10.1186/1756-0500-7-933. [Open access full text] [Blog] [Press]

de Silva, S. (2014).  “The elephant attribute recording system (EARS): A tool for individual-based research on Asian elephants.” Gajah. 40:46. [PDF]

Stoeger A.S., S. de Silva (2014). “African and Asian elephant vocal communication: A cross-species comparison.” In: Biocommunication in Animals. Ed. G. Witzany. Springer, [Full text]

de Silva S., C.E. Webber, U.S. Weerathunga, T.V. Pushpakumara, 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. [Full text & PDF]

Pinter-Wollman, N., E.A. Hobson, J.E. Smith, A.J. Edelman, D. Shizuka, S. de Silva, J.S. Waters, S.D. Prager, T. Sasaki, G. Wittemyer, J.Fewell, D.B. McDonald (2013). “The Dynamics of Animal Social Networks: Analytical, Conceptual and Theoretical Advances.” Behavioral Ecology, DOI: 10.1093/beheco/art047.

Stoeger, A., D. Mietchen, S. Oh, S. de Silva, C. Herbst, S. Kwon, W. T. Fitch (2012). “An Asian elephant imitates human speech.” Current Biology 22(22), 2144-2148. DOI: 10.1016/j.cub.2012.09.022. [Press]

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. [PDF] [Blog]

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[Full text & PDF] [Blog] [Press]   Altmetric score: 85

de Silva, S.R., A. Ranjeewa, D. K. Weerakoon 2011.  “Demography of Asian elephants (Elephas maximus) at Uda Walawe National Park, Sri Lanka based on identified individuals.” Biological Conservation, 144, 1742-1752. [PDF] [Online] [Blog].

de Silva, S.R. 2010. “On Predicting Elephant Population Dynamics.” Gajah, 33, 12-16. [PDF].

de Silva, S.R. 2010. “Acoustic communication in Elephas maximus maximus, the Asian elephant.” Behaviour, 147(7) 825-852. [PDF] [Blog].

de Silva, S.R. 2010. “Asian Elephant Vocalizations.” Corpus of annotated acoustic recordings. Linguistics Data Consortium, Philadelphia. Asian Elephant Vocalizations – Linguistic Data Consortium (

de Silva, S.R. 2010. “Socioecology, Acoustic Communication and Demography of Asian elephants in Sri Lanka.” Doctoral dissertation, University of Pennsylvania. Publicly Accessible Penn Dissertations, Paper 213.

*There are publications of the UWERP. If a paper is not posted, contact us for reprints. For a complete list of publications by S. de Silva, see here.