The dusky langur is a species of monkey native to Malaysia, Myanmar, and Thailand. Categorized as endangered on the International Union for Conservation of Nature’s Red List, these 15-pound, wide-eyed creatures face grave population loss due to human development.
As their native rainforest habitats have been taken over by development, the langurs have been pushed out into urban areas, where they are often killed in traffic collisions, by electrocution from wires, and by being fed unsafe foods.
On Malaysia’s Penang Island — one of the most densely populated areas in the world — researcher Jo Leen Yap knew she had to do something to save the langurs.
Yap is the project executive for Langur Project Penang, but her journey started nearly a decade ago, when, as a student, she noticed many langurs were attempting to cross busy roads by balancing on electrical wires.
Her heart broke as she watched them die by electrocution and collisions with vehicles, specifically the mothers carrying especially vulnerable babies.
Roads like these exist all around the world, killing wildlife of all kinds. Adam Ford, an assistant professor of wildlife restoration and ecology at the University of British Columbia, compares the busy road in Penang to one in Banff National Park.
“They called it the meat grinder,” he told Mother Jones in 2021. “It was bad for people, bad for animals.”
Banff now features a series of overpasses and underpasses that have dramatically helped protect wildlife and people, drastically reducing collisions in the park.
Yap began her conservation work by devising a plan for a similar innovative wildlife crossing to save langurs from the life-threatening road on Penang, too.
LPP started as a citizen science group on Facebook, and as word spread and Yap began her PhD studies at the Universiti Sains Malaysia, the idea for a canopy bridge became a reality.
In 2019, they erected their first bridge above one of the busiest roads in the area, fashioned from recycled fire hoses donated by the Fire and Rescue Department of Malaysia.
While Yap and other researchers considered using other materials like bamboo and nylon, they found that the fire houses would be most practical, as they would hold up in rain and monsoons. They tested them for strength and reliability, and once it was approved, the bridge was lofted 40 feet up in the tree canopy, spanning a 40-foot-wide road.
“We really hope that the canopy bridge is not just to connect the fragments in a large area or even for the roads and highways, but also a conservation tool [to] reduce human-primate conflict,” Yap told Mother Jones. “The ultimate goal is to bridge the gap between humans and urban wildlife.”
A camera on the pole holding up the bridge helps researchers watch over the wildlife of the area, conducting tests and monitoring their behaviors and safety. At first, the langurs were hesitant to use the bridge, and researchers only caught footage of plantain squirrels and long-tailed macaques using the crossing.
So, LPP reinforced the bridge, adding two parallel ropes of twisted firehose. Now, the bridge resembles a horizontal ladder, and the langurs are more keen on using it to cross the road.
Since the bridge was installed, zero mammal deaths have been reported, and more than 7,000 wildlife crossings have been captured on camera.
Now, they’re scaling the solution.
Following the success of the first bridge, LPP is expanding its project around the UNESCO Man & Biosphere Reserve on Penang Island. They’re calling it “Bridge To Coexist,” and plan to install three new canopy bridges by 2026 to reduce roadkill incidents in the area.
So far, one of the three bridges has been installed. Dubbed “Numi’s Crossing,” it was installed in 2024.
“Numi’s Crossing symbolizes hope and peace [and] aims to assist dusky langurs and treetop animals in the area to cross roads safely and to act as an identity of empathy, compassion, and, most importantly, coexistence among humans and urban wildlife in Penang,” LPP’s website shares.
“In less than a week after the bridge installation, the dusky langurs made their first move on the bridge. This is great news to all of us and we’re very inspired by the courage and resilience of urban dusky langurs.”
Now, the LPP team is in the fieldwork stage of planning their next canopy bridge, which will be installed along the Batu Ferringhi Road, ideally by the end of 2025.
In the meantime, Yap and colleagues are also working to raise awareness about human-wildlife coexistence in urban areas and improve outcomes for langurs and all other wild animals like them.
“Dusky langurs live around us, just like other urban wildlife. We are more similar to each other than we think, and we share much more space than you imagine,” Yap shared in a blog post on LPP’s website.
“Facilitating safe spaces for humans and wildlife in urban areas starts with us. Everyone can help make a positive difference in our society by promoting peaceful coexistence among humans and wildlife.”
Header image courtesy of Langur Project Penang
