New Orangutan Species Identified in Sumatra on the Brink of Extinction
This large, gentle red ape is one of the humankind’s closest relatives- sharing nearly 97% of DNA. Orangutans are the enigmatic, great apes found in Asia; congregated on only two islands in southeast Asia that too- on Borneo and Sumatra.
Now, humanity has just recognized a new living cousin.
And exactly when everybody was rejoicing the discovery of the century, scientists said that the newly-discovered species of great ape could soon be extinct if humans keep monkeying around with its environment- that they have surpassed both existing species to become one of the world’s most endangered apes.
The hominid family was once quite diverse, but most of its members are gone. Today it’s just us, two species of gorilla, two chimpanzees, and the orangutans. Two decades ago it became accepted that the orangutans of Borneo and Sumatra are actually separate species, P. pygmaeus and P. abelii, an unsurprising finding given that hundreds of kilometers of sea divide them.
Now, however, scientists from four continents have made the case that
the orangutans that live south of Lake Toba, Sumatra, are a different species from those north of the lake. More remarkably, the north-Sumatran apes are much more closely related to those in Borneo than they are to their relatives a short distance away in the Sumatran forests of Batang Toru.The new species, dubbed Pongo tapanuliensis, probably represents the oldest existing orangutan species, but it’s restricted to a small patch of Sumatran rainforest and is estimated to number just 800.
It all began with an unfortunate encounter in November 2013 between a male orangutan and a group of villagers in the South Tapanuli District of North Sumatra.
The orangutan sustained mortal injuries in the “orangutan-human conflict,” according to a report, and after the animal’s death, scientists studied its skull and compared it with those of 34 other adult male orangutans. They found enough differences to convince them that the Tapanuli orangutan represented a separate species.
It seems that the 800 Batang Toru orangutans split off from the larger Sumatran population over 3 million years ago. They’re actually more related to the other orangutan species—the one living on the nearby island of Borneo—having only split from them about 700,000 years ago.
If you’re wondering how the related apes got from Sumatra to Borneo, note that primates had to cross from Africa to South America at some point around 40 million years ago. Researchers think they were likely carried out to sea on uprooted trees. There’s evidence of other, more recent primate swashbucklers as well. A couple hundred miles of ocean is no match for a half-drowned ape equipped with a floating raft of debris.
The genomic analysis confirmed the uniqueness of the population. Co-author Maja Mattle-Greminger at UZH and colleagues sequenced the genomes of one captive Tapanuli orangutan and 15 from Sumatra and Borneo. The researchers then combined these data with 20 previously published genomes, including another from Batang Toru, to work out a family tree. Alexander Nater, a co-author then at UZH, and the team concluded that by 3.4 million years ago, orangutans in northern Sumatra had split from those in southern Sumatra and Borneo. (The two islands and mainland Asia have been repeatedly joined and separated by changes in sea level.) Then, about 674,000 years ago, the populations in southern Sumatra and Borneo diverged.
“When we realized that Batang Toru orangutans are morphologically different from all other orangutans, the pieces of the puzzle fell into place,” said Dr. Michael Krützen, a professor at the University of Zurich and a member of the research team.
“We have learned how little we actually knew about orangutan evolution despite many decades of research and how much more there is to learn,” Dr. Meijaard said. “Orangutans are ancient creatures, as old as the very first members of our own genus Homo.”
Conservationists say the highest priority is to protect the remaining population, which persists in about 1100 square kilometers of forest. In 2014, the government protected most of the forest from logging. But the best habitat—about 7 square kilometers of lowland forest—is not protected, and villagers sometimes kill orangutans that raid gardens. Gold mining is also driving deforestation.
The orangutans are threatened by hunting and habitat loss. And with fewer than 800 individuals remaining, they’re at risk of going extinct. In comparison, there are an estimated 55,000 Bornean orangutans and an estimated 14,000 Sumatran orangutans in the world. Identifying the new species is the first step to ensure that the Tapanuli orangutans are adequately protected. But it also speaks about how little we still know about the world surrounding us.
The discovery of the third orangutan in the 21st century gives us an understanding that the great apes have more diversity than we know, making it all the more important to conserve these various groups.
Without the strong support of, and participation from, the communities surrounding its habitat, the future of the Tapanuli orangutan will be uncertain. Government, researchers and conservation institutions must make a strong collaborative effort to make sure that this third orangutan will survive long after its discovery.
