In Nepal’s Chitwan National Park and the forests surrounding it, elephants used to be chained for as many as 19 hours a day. The links lay heavy on their ankles, preventing them from moving more than a few inches in any direction and leaving them unable to take shelter from the sun. They stood in their own waste. Some developed arthritis and foot infections.

Even when they were unchained, it was only to work, carrying tourists around on safari or carrying rangers on patrol—work the elephants have been forced to do for generations.

The process of training Asian elephants to carry humans can be brutal, and some captive elephants in Southeast Asia are severely overworked. But since 2014, 83 elephants at camps in around Chitwan National Park have been set free from their chains. Elephant Aid International, a United States-based nonprofit, found success with a new way to contain the elephants: solar-powered electric fences.

This setup lets the elephants engage in some natural behaviors, an important indicator of animal welfare. They can walk and lie down, play and socialize, dust and bathe.

View Images When not working, elephants at Chitwan National Park in Nepal used to spend all their time in chains. Now, almost all live chain-free in corrals. Photograph by Gemunu Amarasinghe, AP Images

“Chain-free corrals provide a safe and nurturing space for captive-held elephants to experience autonomy and freedom from harsh treatment for the first time in their lives,” says Carol Buckley, the founder of Elephant Aid International.

In Nepal today there are about 200 elephants in captivity, compared to approximately 140 in the wild, according to a 2011 report. More than half are privately owned, and those elephants mainly work in tourism. The others are held by the government and primarily carry rangers on anti-poaching patrols or help with scientific research by carrying equipment deep into the forest.

In Southeast Asia overall, as as many as 20,000 elephants are used in tourism, toil in the logging industry dragging felled trees, take forest rangers on patrol, and perform in religious ceremonies. (Read more: "Q&A with Elephant Aid International founder Carol Buckley")

Elephants in Captivity

Nepal’s history with captive elephants dates back to at least the fifth century A.D., when kings in the Licchavi dynasty used elephants in war to clear roads, transport supplies, and carry fighters into battle, according to Piers Locke at the University of Canterbury in New Zealand. The elephant later came to symbolize royal power in Nepal, and Hindu texts are full of examples of the importance of elephants, who to this day play their part in religious ceremonies.

So far, Elephant Aid International has built chain-free corrals at 23 locations in Nepal, Thailand, and India, helping more than a hundred elephants. The solar-powered electric fences need only about three hours of sunlight to stay charged for 10 days—a critical advantage in rural parts of Southeast Asia, where electricity may run only a couple of hours each day.

The fences are the same voltage as most typical livestock electric fences. The 10,000 volts give enough of a shock to keep most elephants away from the wires. But the shocks rile up some bulls, causing them to break the fences with their tusks, so Buckley is working on strengthening them.

The bottom line for Buckley is that even though freeing the elephants from their chains is a help, it’s unacceptable that they’re still captives. “Bringing them into captivity only exposes them to a slower, more painful death,” Buckley told National Geographic in 2013. That was reinforced by a Seattle Times investigation into the well-being of elephants in zoos in the U.S., which are arguably better off than the working elephants of Southeast Asia because of stricter regulations and oversight. It found that captive elephants have an infant mortality rate triple that in the wild and that life spans were significantly shorter.

But getting them “chain-free [and] pain-free,” is a start toward improving the lives of captive elephants across Asia, Buckley says. “The joy they show when they’re freed from chains—you cannot mistake it. It is pure joy.”

Watch the video above to go behind the scenes with Buckley at one of the chain-free elephant camps in Nepal.