JAKARTA, Indonesia – A Sumatran orangutan has been filmed for the first time using a human-made canopy bridge to cross a public road on the Indonesian island of Sumatra, conservationists said Monday.
Rapid development has shrunk the jungle habitat of the critically endangered species, increasing fatal conflicts with people.
The fleeting scene, captured by a motion-sensitive camera, shows a young Sumatran orangutan pausing at the forest’s edge, gripping a rope with deliberate care and stepping into open air. Halfway across, it stops and glances down at the road below. Moments later, it crosses.
Conservationists say the footage marks the first documented case of a Sumatran orangutan using an artificial canopy bridge to cross a public road that divided its habitat.
“This was the moment we had been waiting for,” Erwin Alamsyah Siregar, executive director of Indonesian conservation group Tangguh Hutan Khatulistiwa, or TaHuKah, told The Associated Press. “We are very grateful that the canopy here provides benefits for orangutan conservation efforts.”
Siregar said the bridge spans the Lagan – Pagindar Road in Pakpak Bharat district, a vital corridor connecting remote villages to schools, health care and government services. The road cuts directly through prime orangutan habitat, splitting an estimated 350 orangutans into two isolated forest areas: the Siranggas Wildlife Reserve and the Sikulaping Protection Forest.
When the road was upgraded in 2024, the gap in the forest canopy widened, eliminating natural crossings for tree-dwelling wildlife.
“Development was necessary for people,” Siregar said. “But without intervention, it would have left orangutans trapped on either side.”
TaHuKah, working with the Sumatran Orangutan Society, or SOS, and local and national government agencies, proposed a simple solution: rope bridges suspended between trees that allow arboreal animals to cross above traffic.
Five canopy bridges, each fitted with a camera trap, were installed after surveys of orangutan nests, forest cover and animal movement. The structures were designed to support an orangutan’s weight, no small feat for the world’s largest tree-dwelling mammal.
The program is closely monitored, with camera traps on every bridge and regular patrols to prevent forest encroachment. Conservationists hope more orangutans will follow the first pioneer.
They waited two years for the first orangutan to cross. Before that, only smaller animals used the bridges. Camera traps recorded squirrels, langur monkeys and macaques, followed by gibbons, a promising sign.
The orangutan’s approach was slower, with nests built near the bridge, lingering at its edges and repeated testing of the ropes.
“They observe,” Siregar said. “They don’t rush. They watch, they try, they retreat. Only when they’re certain it’s safe do they move.”
Then one day, the orangutan crossed fully, a first not just for Sumatra but for the species globally on a public road, conservationists say.
Similar bridges have been used by orangutans elsewhere, usually over rivers or on private industrial forest roads. Conservationists say public roads, noisy, busy and unpredictable, pose a far greater challenge.
For orangutans, the stakes are high. Isolation leads to inbreeding, genetic weakening and eventual population collapse. Restoring connectivity gives them a chance to survive.
Once widespread across southern Asia, the species now survives only on the islands of Sumatra and Borneo. Fewer than 14,000 Sumatran orangutans remain in the wild, alongside about 800 Tapanuli orangutans and roughly 104,700 Bornean orangutans, according to conservation groups.
“These bridges allow orangutans to move, to mix, to maintain healthy populations,” Siregar said. “It reduces the risk of extinction.”
