Newly discovered orangutans already face extinction

  • Animals
  • Thursday, 16 Nov 2017

A Tapanuli orangutan eating some leaves at the Batang Toru Forest, North Sumatra. Photo: MAXIME ALIAGA

They have a prominent moustache, frizzier hair textures and larger canines. The females even sport beards!

Primate researchers were all abuzz last week when a new species of orangutan known as Tapanuli was confirmed. This is the third orangutan species to be found, after the Borneon orangutan (Pongo pygmaeus) and the Sumatran orangutan (Pongo abelii).

But its name should not be confused with Tamparuli, a place in Sabah famous for a song about the town’s bridge, Rather, the Tapanuli orangutan (also known as the Batang Toru orangutan or by its Latin name Pongo tapanuliensis) lives in a part of Indonesia close to Penang.

The journey of discovery started in 2013 when researchers got hold of the skeletal remains of an orangutan from the Tapanuli region in North Sumatra.

After four years of research involving 37 scientists from 10 countries, including Malaysia and Indonesia, the experts confirmed the new species.

Tapanuli orangutan
Dr Goossens says the Batang Toru orangutans seem to be direct descendants of the initial orangutans that had migrated from mainland Asia. Photo: Filepic

“In terms of research, it’s not every day that a new species of apes is described,” said Dr Benoit Goossens, wildlife researcher and head of the Danau Girang Field Centre in Kinabatangan, Sabah.

These furry fellows were connected to Sumatran orangutan populations (Pongo abelii) to the north until 10,000 to 20,000 years ago, before they became isolated.

“The Batang Toru orangutans appear to be direct descendants of the initial orangutans that had migrated from mainland Asia. They are the oldest evolutionary line within the genus Pongo.”

The combination of skull, jaw and teeth measurements plus genetic analyses, as well as behavioural differences, allowed the scientists to characterise them as a distinct species, explained Goossens.

The newest ape stars are named after the two places where they are found, at three districts in Tapanuli regency (sub-province) in Northern Sumatra. This lies within the 150,000ha Batang Toru Ecosystem conservation area in Sumatra, about an eight-hour drive southwards from Lake Toba.

They feature some distinct characteristics; the male long call has a higher maximum frequency range and their hair texture is frizzier, compared to the long, loose body hair of the Sumatran orangutan.

Dominant males are also seen having a prominent moustache and flat flanges covered in downy hair, while flanges of older males look similar to those of Bornean males. Female Tapanulis also sport beards, something not present among Bornean orangutans.

Tapanuli orangutan
The new species of Tapanuli orangutans has frizzier hair than Sumatran orangutans like Inda here. Photo: Tim Laman

In terms of bone structure, the new species has a smaller skull but larger canines compared to the other two species.

Broken homes, inbreeding

There are currently only about 800 of the Tapanuli orangutans in existence, and conservation is urgently needed to protect the species from extinction.

“[They are] now the rarest and most threatened great ape species in the world,” said Dr Nadine Ruppert, senior lecturer on primate research and conservation at Universiti Sains Malaysia’s School of Biological Sciences.

It was reported recently in that the director-general of conservation of natural resources and ecosystems at Indonesia’s Forestry and Environment Ministry said that most of the Batang Toru forest was designated as protected in December 2015 and that the government is “committed to ensuring the species’ survival”.

The majority of the Batang Toru Ecosystem is already listed as “Protected Forest” and only 15% of forests there are designated for “Other Use Areas” or “Production Forest” (where logging is allowed), explained Ruppert.

“The majority of the orangutan habitat in this area (110,000ha) is 850m above sea level, which is hopefully an elevation that offers at least some protection from human threats,” she added.

Activities that threaten the survival of the Batang Toru orangutans include poaching, habitat loss and fragmentation due to land conversion, illegal road construction, killings during human-orangutan conflicts and illegal trade.

Tapanuli orangutan
Lappan says the Tapanuli orangutans need large patches of forest to support populations that are large enough to survive in the long run. Photo: Maxime Aliaga

“Fragmented habitats force orangutans to look for food and shelter in areas close to human settlements. There, they are often killed by people out of fear or greed, or for consumption. Often mothers are killed to obtain their infants that are sold off as pets,” said Ruppert.

Another major concern is a proposed hydroelectric development in the area where the density of orangutans are high. The project stands to affect up to 8% of the new species’ habitat and will lead to genetic impoverishment and inbreeding.

Goossens cautioned that the hydroelectric development would jeopardise the chances of maintaining habitat corridors between the western and eastern (mountain) ranges.

Apes need space

“Therefore, drastic conservation measures must be taken to make sure that Pongo tapanuliensis does not get extinct soon after being described,” he urged.

Dr Susan Lappan, primate behavioural ecology and conservation expert, said orangutans require large patches of forest to support populations that are large enough to persist in the long term.

“It is not enough to protect a few orangutans in isolated forest fragments. The conservation focus should be on protecting all of their habitat, and where possible, re-establishing connectivity between existing fragments,” she explained.

“Fragmentation of the species into disconnected habitats increases the risk of extinction,” added Lappan, “because small populations are more vulnerable to inbreeding, depression and extinction due to fluctuations in environmental, social, or demographic conditions.

“So the establishment of habitat corridors between the forest fragments should be considered where possible.”

Ruppert said that orangutans have a slow breeding interval of eight to nine years and need a large home range to forage for food.

Tapanuli orangutan
The new Tapanuli orangutans are the rarest and most threatened great apes in the world, says Ruppert. Photo courtesy of Dr Nadine Ruppert

Thus, forest fragmentation and hunting speeds their decline. For a very small population like the Batang Toru orangutans, these threats are even more severe, she said.

Goossens urged that enforcement in the Batang Toru area be increased to make sure that the entire range is totally protected.

“We also need to make sure that the new species is quickly listed in the (IUCN) Red List as critically endangered. Reestablishing connectivity between isolated populations would be required as well,” he said.

Orangutans are the only great apes found in Asia.

“Indonesia and Malaysia are blessed to be the habitat countries for these iconic and amazing primates,” said Ruppert.

“I hope that with the discovery of this new species our countries and the international community can strengthen their efforts for orangutan conservation to ensure a future where our grandchildren will still be able to see these apes in the wild.”

Lappan added that the forests where the Tapanuli orangutan live are not just important to them, but also to humans, because of the services that they provide, such as providing fresh water, reducing erosion and preventing floods plus carbon storage.

She has a wish: “I hope that even after the initial excitement surrounding this new species dies down, our governments, NGOs, and the public will continue to do everything in their power to protect wild orangutans and other endangered wildlife.”

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