Indonesia is racing to preserve the last frontier for a vanishing primate.
The Javan gibbon is only found on Java - which is Indonesia's most populous island.
The gibbons play a vital role dispersing seeds and regenerating the forest, but researchers worry that their already endangered numbers are dwindling.
Their habitat could also be hit further impacted by a changing climate and human activities from hunting to agriculture.
Conservationists say there are roughly 4,000 Javan gibbons left on the island.
Arif Setiawan has spent more than a decade monitoring the animals with the conservation group SwaraOwa.
He says the 400-strong population of gibbons in a reserve they monitor is stable.
But now he worries for the habitat itself.
"The real threat now is the integrity of the forest itself because of the increasing number of human activities. Many people are encroaching on the forest as well, clearing the forest which was originally the habitat of the gibbons."
SwaraOwa also work with the government hold monthly outreach programs with the local community and set up signs to try and ward off illegal hunting and logging in the forest.
Conservationist Untoro Tri Kurniawan says changes in the climate are a more complex challenge.
"It is still raining when it supposed to be the dry season and that will eventually impact the vegetation. Instead of fruiting season, leaves grow. So the flower that is supposed to become fruit could decline and eventually impact the animals."
Meanwhile SwaraOwa have worked to provide locals alternative ways to make money that don't take a toll on the gibbons' home.
They've set up local accommodation and tours focused on sustainability and work with local village chiefs on farming shade-grown coffee.
It's delicate balance to strike and the clock is ticking.
Another group, the Silver Gibbon project, warns there's 50/50 chance the animals will disappear in the next decade.