Study: losses outpacing newcomers fractured elephant society in Sri Lanka's Udawalawe park

Mixed · 2A study published in Science on 12 November 2026 reports that the social network of wild female Asian elephants in Udawalawe National Park, Sri Lanka, fragmented after losses of individuals began to outpace new arrivals. 1 2 Mixed · 2The work was led by Anastasia Madsen, a behavioral ecologist at the University of California, San Diego, with Shermin de Silva, an ecologist at the university and senior author, who started the Udawalawe Elephant Research Project in 2006. 2 1 Left · 1Between 2007 and 2018 the team identified 443 adult and subadult females, mostly by the distinctive holes, tears and cuts in their ears, while driving park roads about three days a week. 2

Left · 1Madsen reconstructed a social network for each year, based on how often two animals were seen together, and used an algorithm common in human network analysis to identify communities. 2 Mixed · 2Around 2012, departures and deaths began to exceed newcomers; by 2018 about 69 percent of the females seen at the start were gone, and communities then became smaller, more numerous and more isolated from each other. 2 1 Mixed · 2The change was not just a matter of fewer animals: among 59 resident elephants seen every year, relationships changed too, with fracturing coming one to three years after the decline began, and the weakest ties disappeared first. 2 1

Left · 1Madsen suspects some lost individuals were key animals holding subgroups together, and de Silva links the shrinking social sphere to growing competition for food as grass disappears. 2 Left · 1According to de Silva, the park's grassland, which formed after settlers were moved out, has been overtaken by invasive plants such as lantana that offer elephants little food; she says this stops the park attracting elephants from outside and means fewer calves reach adulthood. 2 Left · 1Madsen says fluctuating network statistics before the break-up resemble 'flickering' and could serve as an early warning sign, though detecting it requires long-term data that many populations lack. 2

Left · 1The study data end in 2018, but de Silva says conditions have not improved: the team predicted a decline in 2019, and it appears to be happening faster than expected, with calves not surviving and many adult females dying in their 30s and 40s. 2 Left · 1Ars Technica adds that human conflict contributes, as elephants are shot when raiding crops, and de Silva argues management must cover whole landscapes, including roads and irrigation canals; her team now works with farmers on crops elephants are less likely to damage. 2 Centre · 1The Times of India, drawing on a UC San Diego announcement, stresses that the study does not attribute every disappearance to a single cause and that its findings concern how accumulated losses were associated with social change; it says the researchers warn the fragmentation may be hard to reverse once a tipping point is crossed. 1