PALANGKARAYA • Orang utans are falling victim to the haze crisis. It has left them sick, malnourished and severely traumatised as fires rage through Indonesia's forests, reducing their habitat to a charred wasteland.

Rescuers at a centre for the endangered great apes on Borneo island are considering an unprecedented mass evacuation of the hundreds in their care, and have deployed teams on hazardous missions to search for stricken animals in the wild.

At the Nyaru Menteng centre in Kalimantan, 16 baby orang utans have been put into isolation. They are suffering infections from prolonged exposure to the thick yellow smoke suffocating Borneo.

In another enclosure, several orang utans lie about listlessly, too exhausted to move after days of hunting for food and water as fires relentlessly encroached on their forest homelands, forcing them to flee.

Others swing repeatedly from bar to bar, occasionally pausing to make a distinct smacking with their lips.

"That's called a quick kiss," said Mr Hermansyah, a caregiver at the centre, who like many Indonesians goes by one name. "When they make this gesture, it means they are under tremendous stress."

Staff at the centre say the intensity of the smoke and flames at ground zero has never been seen before. Many rescued orang utans are malnourished and dehydrated. Some have required surgery for infections exacerbated by the haze, while others have been too scared to venture for long outside their enclosures.

The pace and scale of the approaching fires have forced programme manager Denny Kurniawan to consider an unprecedented scenario - a full-scale evacuation of all 470 orang utans in their care.

"This year's disaster is definitely the worst since 1997," he said, referring to the worst-recorded haze crisis in history. "We've never been forced to evacuate orang utans or draw up an emergency contingency plan, but these fires are beyond crazy. Why haven't we learnt anything? Why does this keep happening?"

AGENCE FRANCE-PRESSE