Evrim Yazgin
Cosmos science journalist
The saola is a rare antelope-like mammal endemic to the forests of Vietnam and Laos. It hasn’t been seen in the wild since 2013, leading to it being nicknamed the “Asian unicorn” for its elusiveness. But scientists still think it can be saved from extinction.
Saola (Pseudoryx nghetinhensis) are in the same group as buffalo, cows and antelope, but belong to their own unique genus.
The species is the most recently discovered large mammal in the world, first described in 1992 after being spotted in Vietnam’s Vu Quang National Park. It was already endangered. Even the most optimistic estimates suggest fewer than 100 saola individuals remain in the misty highland forests of Vietnam and Laos.
Getting a reliable indication of whether the saola still roams is made difficult by its remote, rugged forest habitat.
But some wildlife experts believe there is hope.
“Right now, the existence of live saolas can neither be proven nor disproven,” says Nguyen Quoc Dung from the Forest Inventory and Planning Institute in Vietnam. “The last evidence we have was from 2013, when one was captured on a camera trap. But given the remoteness of its habitat, it is extremely difficult to say for sure whether there are still a few out there. There are some signs and indications that still give us hope.”
Nguyen is co-author on a paper published in the journal Cell which includes the first genome map of the saola.
Complete genomes were generated for 26 saola individuals using remains from hunters’ households.
The information sheds light on the species’ past and presents insight into its future.
“We were quite surprised to find that the saola is split into 2 populations with considerable genetic differences,” says lead author Genís Garcia Erill, from Aarhus University in Denmark. “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.”
Genetic data also suggest that the saola population has been declining since the last ice age, never more than 5,000 individuals in the last 10,000 years.
While the 2 distinct populations have seen a decline in genetic diversity – key to a species’ long-term adaptability and survivability – they haven’t lost genetic diversity in the same way.
“This means that the genetic variation lost in each population complements the other. So, if you mix them, they could compensate for what the other is missing,” says Garcia Erill.
This could be the key to saving the saola from extinction.
“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 in Denmark. “That has worked before when species were on the brink of extinction.”
The problem is actually finding 12 saola individuals in the first place.
“Many researchers have unsuccessfully tried to find traces of saola through methods like environmental DNA in water and even in leeches in the same habitat. These techniques all rely on detecting tiny DNA fragments, and now that we know the complete saola genome, we have a much larger toolkit for detecting those fragments,” says co-author Minh Duc Le from Vietnam National University.
Even if there are no saola left, the new research’s findings may still be useful.
“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,” says Rasmus Heller. “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.”
