Deep in the mist-shrouded forests of the Annamite Mountains, on the border between Vietnam and Laos, lives a mysterious, horned creature. At least, that's where it used to live.
Nicknamed the 'Asian unicorn' for its elusiveness, the saola (Pseudoryx nghetinhensis) is a striking antelope-like mammal that has barely been glimpsed since it was first discovered in 1992. The last confirmed sighting in the wild was over a decade ago, in 2013.
Could the saola already be extinct? Or is it hiding in the remote highland forests where few humans ever tread?
That's what the researchers of a new international study, published in the journal Cell, wanted to find out. By mapping the saola’s genome (and therefore gaining a complete set of genetic material of the species) for the first time ever, the team say they have unlocked secrets about the animal's evolutionary history and survival prospects.
A vanishing act
With the aid of physical remains (such as skulls and skins), anecdotal evidence from locals, and five observations from camera-trapping surveys, we know that the saola measures around 85cm at the shoulder and has striking white markings and large glands on its face.
Perhaps the animal's most iconic feature is its horns, which can reach 50cm in length and are found on both males and females.
But the saola is precariously rare; even when it was first described, it was already critically endangered. Today, estimates suggest that fewer than 100 individuals remain – if any at all.
"Right now, the existence of live saolas can neither be proven nor disproven," says Nguyen Quoc Dung from Vietnam’s Forest Inventory and Planning Institute. "The last evidence we have was from 2013, when one was captured on a camera trap."
The saola’s forest habitat – dense, rugged and almost impenetrable – is both a blessing and a curse. While it may shield the animals from human activity, it also makes finding them incredibly difficult, says Dung, adding that "there are some signs and indications that still give us hope."
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Unlocking ancient secrets
In the new study, researchers analysed genetic material from 26 saolas, using samples collected from local households that once hunted the animals. This has revealed unexpected new insights.
"We were quite surprised to find that the saola is split into two populations with considerable genetic differences," says Genís Garcia Erill, lead author of the study.
"The split happened between 5,000 and 20,000 years ago. That was completely unknown before, and there was also no way we could have known without genetic data.
"It is an important result because it affects how the genetic variation in the species is distributed," says Erill.
Importantly, while both groups have lost genetic diversity over the last 10,000 years, they’ve lost different parts. This means combining them could create a stronger, more resilient population – a crucial finding for any future breeding effort.
Can the saola be saved?
The research team modelled different conservation strategies and found that the best chance of saving the saola lies in establishing a captive breeding programme using individuals from both populations.
"If we can bring together at least a dozen saolas – ideally a mix from both populations – to form the foundation of a future population, our models show the species would have a decent chance of long-term survival," says senior author Rasmus Heller from the University of Copenhagen.
"But it hinges on actually locating some individuals and starting a breeding program," says Heller.
That’s where the new genetic map could prove invaluable. With the full genome now available, scientists can refine techniques such as environmental DNA analysis – scanning water sources or even leeches for traces of the saola’s DNA to help them locate the animals.
But Heller remains cautious. "Scientists have been searching for saolas since the 1990s, and it’s only gotten harder since then, because there were more of them back then. I’m not overly optimistic, I have to admit – but I really hope the saola is still out there."
Back from the dead
Even if the saola has vanished, the new findings still matter, says Heller. The genome could one day support efforts to resurrect the species using emerging genetic technologies.
"Our results could in theory be used if we were ever to succeed in bringing the saola back through genetic de-extinction technologies, which are a hot topic right now. In that case, our new insights into saola genetic variation could make a huge difference in creating a viable population."
Find out more about the study: Genomes of critically endangered saola are shaped by population structure and purging
Main image: mountain rainforest in Laos. Credit: Getty
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