East Kutai. The Forestry Ministry has recently released four fully-grown orangutans in East Kutai Regency, East Kalimantan, an official said on Thursday.

These four orangutans were released after undergoing a rehabilitation process by the Bornean Orangutan Rescue Alliance (BORA) in the government-protected forest area in Berau Regency.

Subsequently, they were released in the Gunung Batu Mesangat Protected Forest, which is managed by the Kelinjau Forest Management Unit and in collaboration with the Centre for Orangutan Protection (COP).

"Their release aims to provide an opportunity for these formerly captive orangutans to live freely in the wild. It also contributes to increasing the orangutan population in its natural habitat," said Ari Wibawanto, Head of East Kalimantan’s Natural Resources Conservation Center.

The four orangutans are named Paluy, Bonti, Jojo, and Mary. Paluy, an 18-year-old male orangutan, was taken to the rehabilitation center in July 2024 to undergo medical treatment.

Meanwhile, Bonti, Jojo, and Mary, all female, were previously kept as pets by residents and were evacuated between 2017 and 2019. Mary is currently 10 years old, while Bonti and Jojo are both 12.

Ari said pet orangutans need to undergo rehabilitation to restore their natural behaviors and break their dependency on humans. At the rehabilitation center, they adapt to live independently in the forest.

"The release process went smoothly. The orangutans were observed to be active, exploring the forest and searching for food. The COP monitoring team will follow the four orangutans for three months to ensure they are safe and adapt well to their new forest environment," said Ari.

The release aims to provide a chance for the ex-captive orangutans to live in the wild and increase the orangutan population in their natural habitat. 

According to data from the Forestry Ministry, the Bornean orangutan (Pongo pygmaeus) population is estimated at 57,350 individuals in a habitat of 16 million hectares, spread across 42 population pockets. Of these, 18 are predicted to remain sustainable for centuries ahead. This data updates a previous estimate from 10 years ago, which projected the population to be 54,817 individuals in a habitat of 8.2 million hectares, based on a more limited study area.