Unknown Orangutan Population Discovered in Borneo

Orangutans belong to the Hominidae family, also called the great apes. They are highly intelligent and share around 97% of their DNA with humans. Orangutans are the only great apes in Asia and make their homes on the islands of Borneo and Sumatra in the Malay Archipelago. Orangutans are arboreal, meaning they primarily live in trees. There are three subspecies of orangutans, including the Bornean orangutan, the Sumatran orangutan, and the Tapanuli orangutan, which was only found in 2017.

The International Union for Conservation of Nature (IUCN) lists all three subspecies of orangutans as critically endangered. Their numbers have decreased by more than half over the last 60 years. Exact population counts are difficult to ascertain, but the World Wildlife Fund estimates there are only 120,000 orangutans left in the wild across all species. They have a low reproductive rate, giving birth only once every 5-10 years, making it difficult to increase their numbers. However, the discovery of a previously unknown orangutan population in Malaysian Borneo is reason to hope.

Threats

Deforestation, illegal logging, and mining have been devastating to the ecosystem, reducing orangutan habitats by more than 80% over the past 20 years. Researchers estimate that one-third of the wild population was killed during forest fires in Indonesian Borneo in 1997-1998. Unfortunately, many orangutans live outside of protected regions, putting them at greater risk.

The encroachment on orangutan habitats sometimes forces them into agricultural land, where they are in danger of being shot. Threats from poaching and the illegal pet trade are also considerable. Studies have shown, according to the World Wildlife Fund, that as many as 200 to 500 orangutans from Indonesian Borneo alone are lost to the illegal pet trade every year. Enforcement of the laws prohibiting the sale or trade of orangutans is notoriously difficult. Due to their high intelligence, rehabilitation for rescued orangutans is complicated, and it may take years before they can be released back into the wild.

An Incredible Discovery

It’s not all bad news, though. In 2013, reports in mainstream news outlets reported the discovery of a new orangutan population in Sarawak, Malaysian Borneo; it was cause for excitement among conservationists. They were shocked to find up to 200 members of the most severely threatened population of Bornean orangutans.

The subspecies Pongo pygmaeus pygmaeus has only around 3,000 to 4,500 left in the wild. At least 2,000 of this number live in Batang Ai National Park and Lanjak-Entimau Wildlife Sanctuary in Sarawak.

This population of orangutans, however, wasn’t completely unknown to local communities. According to Robert Basiuk, cofounder and executive director of Borneo Adventure, “[The orangutans] were in fact one of the focuses of our tour company, Borneo Adventure, which started operating ecotours in the area in 1987.” He continued, “What was unknown (at the time) was that logging licenses had been granted over much of the area outside Batang Ai National Park [where the new population was discovered] and adjacent to the Indonesian border.”

This led to research efforts between the Sarawak Forest Department, Sarawak Forestry Corporation, the Wildlife Conservation Society, and Borneo Adventure. Researchers conducted field surveys across 150 miles of central Borneo and confirmed the presence of nearly 1,000 fresh nests across the area.

“The results of two rounds of surveys revealed that there were indeed a significant number of nests indicating a population of up to 200 orangutans,” Basiuk said. “It should [also] be noted that this area is also the traditional homeland of the Iban people, many of whom had been earning money from wildlife tourism in the area since 1987.”

When learning of the globally significant population of this endangered subspecies and the economic boom it provided the Iban people, the Sarawak government officially indicated its priority to permanently protect the area.