Nocturnal Pulse: Usun Apau Ancient Forest

You would not believe how a tropical rainforest can be so loud and active at night. This is a rich nocturnal insect chorus deep within one of Borneo’s last pristine wilderness areas. The area is a very remote plateau called Usun Apau, which has remained completely untouched and unchanged since the dawn of time. The constant chorus is occasionally punctuated by the distinct calls of night creatures, each occupying its acoustic space. As the recording progresses, the chorus slowly develops into a more complex and lively ambience.

About Usun Apau

Usun Apau is an isolated volcanic plateau situated deep within Borneo’s interior, making it one of the most biologically significant yet one of the least explored and accessible areas in Sarawak. This elevated landform, characterized by ancient lava flows and dramatic waterfalls including the huge, 100m high Julan Waterfall, represents one of the final frontiers of truly virgin forest in Sarawak. The plateau is elevated at approximately 1,000 meters above sea level and represents a rare 471.22 km² sanctuary of untouched rainforest in the true Heart of Borneo.

I made an independent expedition here in February 2025 that required an 8-hour drive on challenging logging roads followed by a hard trek through unmarked jungle mountain terrain spending 3 nights camping in the wild jungle. This remote mountain also holds cultural significance as a sacred birthplace for the indigenous Kenyah and Kayan peoples which according to the local knowledge descended from the plateau down to the valleys. “Usun” means “on top of” and “Apau” means “plateau” in the local dialect.

Few scientific expeditions have ventured here with each visit making discoveries, including the presence of orangutans in this region that were previously undocumented and thought they did not live in this area of the island.