Today, one third of the world’s Asian elephants—numbering roughly 15,000—live in captivity. Some are housed in zoos or research facilities, while others are held by private owners. The largest population of these creatures, however, exists in Myanmar, where roughly 5,000 elephants form the backbone of the country’s timber logging industry.
Myanmar’s captive-born and wild-captured timber elephants live side-by-side, working by day and scavenging for food by night. Both are tamed and trained prior to entering the workforce, and both are subject to government regulations regarding workload and rest periods—including holidays, maternity leave and a mandatory retirement age. Still, a new study published in Nature Communications suggests that the two groups face vastly different risks, with wild-captured elephants exhibiting higher mortality rates than those bred in captivity.
Cosmos Magazine’s Tanya Loos reports that researchers from Finland’s University of Turku and Berlin’s Leibniz Institute for Zoo and Wildlife Research used extensive demographic records to assess the life spans of captive-born versus wild-captured timber elephants. The dataset featured life histories of 5,150 elephants, including 2,072 captured between 1951 and 2000 and 3,078 born in captivity between 1925 and 1999. They also recorded wild-captured individuals’ age at capture, method of capture and age at death.
“We chose to rely on data from timber camps as—their capture aside—both wild-caught and captive-born elephants have very similar lifestyles,” said study co-author Alexandre Courtiol, a data scientist at the Leibniz Institute, in a statement. “This unique situation allows a comparison between these two groups unbiased by other factors such as diet or exercise.”
The team found that wild-captured elephants exhibited a median lifespan three to seven years shorter than that of captive-born elephants. This heightened mortality rate proved consistent regardless of the capture method used. As Josh Gabbatiss writes for The Independent, the capture process is stressful for elephants, who are individually sedated or lassoed or driven against pre-constructed barriers in large groups.
According to the study, potential explanations for wild-captured elephants’ shorter life expectancies are chronic stress triggered by a traumatizing capture, disruptions in environment and changing interactions with humans and other elephants. Additionally, although captive-born and wild-caught elephants are trained alongside one another, wild-captured elephants may be exposed to harsher treatment based on their age, sex and personality.
The detrimental effects associated with capture proved more harmful to older elephants than younger ones, lead author Mirkka Lahdenperä, a biologist at the University of Turku, noted in a statement. Although the mortality rate of wild-captured elephants peaked during the first year following capture, slowly decreasing thereafter, negative effects persisted for up to a decade.
The researchers’ findings have important implications for conservation efforts. Currently, more than 60 percent of the world’s zoo elephants are captured from the wild. Large-scale capture of wild elephants is also used to supplement existing captive populations, a practice the team views as “costly” given the associated risks to individual longevity.
“Capturing elephants to sustain captive populations is … detrimental, because it not just reduces wild populations of this endangered species, but it also cannot provide a viable solution to sustain captive populations,” said the study’s senior investigator Virpi Lummaa, a biologist at the University of Turku, in a statement. “These wild-caught animals live shorter lives and reproduce poorly in captivity.”
If capture is unavoidable, perhaps due to immediate conservation needs or poaching threats, the researchers encourage veterinarians and biologists to provide support and care during the critical period of immediate aftermath. Overall, the team cites the need for developing alternative solutions that boost captive populations without further endangering wild populations.