There are no saolas in captivity, and fewer than 100 may remain in the wild.

Not much is known about the saola, a mysterious horned mammal native to forests in the Annamite Mountains of Laos and Vietnam. At least one thing seems fairly certain, though: The saola is a very endangered species.

It’s unclear exactly how many saolas exist, and there is scant information on which to base even loose estimates. The species was unknown to Western science until 1992, when researchers encountered saola horns in the home of a local hunter. It remains incredibly elusive, especially for an animal of its size (which is why it’s sometimes called the “Asian unicorn,” even though it has two horns, not one). Scientists have only managed to record a saola in the wild five times—and only with camera traps.

Based on a combination of factors, however, it’s clear the saola is in trouble. It’s listed as critically endangered by the International Union for Conservation of Nature (IUCN), which estimates six to 15 isolated subpopulations are left, each with just tens of individuals. The species’ total population is “undoubtedly less than 750, and likely much less,” according to the IUCN. Some estimates suggest fewer than 100 saolas remain.

Despite meager data, all available information about the saola points to a “clear and protracted decline throughout its small range,” the IUCN warns, noting the rate of decline is poised to continue worsening. And with zero saolas in captivity anywhere on Earth, the loss of wild populations would mean the loss of the species.

Here is a closer look at what little we know about this elusive bovid, including why it’s endangered, how people are trying to save it, and what you can do to help.

Saola horns at the Zoological Museum, Copenhagen.

Threats 

The saola (Pseudoryx nghetinhensis) belongs to the taxonomic tribe Bovini, which also includes all wild and domestic cattle as well as bison. Yet it’s the only surviving member of the Pseudoryx genus, having diverged from all other living bovids more than 13 million years ago, so it’s only distantly related to other species.

Adult saolas stand about 33 inches tall at the shoulder, but they can weigh 220 pounds, and their two parallel horns—found on both males and females—can grow 20 inches long. They may be smaller than most cattle and bison, but few animals of their size have managed to hide from humanity as well as saolas have. They are likely the world’s largest land animal that has never been seen in the wild by a biologist, according to the IUCN’s Saola Working Group.

Unfortunately, not even the stealthy saola can hide from humans entirely. While it continues to evade scientists, the saola is nonetheless suffering the effects of humanity’s presence, both directly and indirectly.

Hunting

Hunting is the main danger for the saola, according to the IUCN, even though most hunters in the species’ range have little interest in killing or capturing it. Local wildlife is mainly hunted for the bushmeat or traditional medicine trades, and specific demand for saola is “almost non-existent” in either trade, the IUCN explains.

Unlike many other animals in its habitat, the saola is not featured in the traditional Chinese pharmacopeia, so there isn’t much financial incentive for hunters to target saolas for export. The species’ meat is not considered especially appealing compared with other, more common ungulates in the same forests, like muntjacs or sambar deer, so it isn’t highly valued as bushmeat, either.

Yet that does not mean saolas are safe. Even though they aren’t the target of most hunters in the Annamite Mountains, they’re often incidentally killed amid the general pursuit of other wildlife for the region’s intensive wildlife trade. Some saolas fall victim to bushmeat hunters, but the main threat comes from wire snares set by professional poachers, according to the Saola Working Group.

The scale of hunting and trapping in the saola’s range is "hard to adequately describe," according to the IUCN. Wildlife like bears, tigers, and sambar are widely killed in large numbers with indiscriminate means—namely snares—that also claim non-target species like saolas. And while some species in the Annamites may be populous and widespread enough to withstand this onslaught, the saola has much less of a buffer.

Saola hooves on display at Zoological Museum, Copenhagen.

Habitat Loss

Another major threat to the saola is a familiar one for wildlife all over the world: the loss and fragmentation of its habitat. Human development has helped isolate various subpopulations from one another, with barriers ranging from roads and farmland to mining and hydropower development.

The development of the Ho Chi Minh Highway, for example, has reportedly already affected saola subpopulations by fragmenting forests, as well as by increasing human access for logging, hunting, and spiriting wildlife away to urban markets. The road has also led to more deforestation in several key areas for the saola, according to the IUCN, especially the Hue Saola Nature Reserve and Quang Nam Saola Reserve.

There are between six and 15 subpopulations of saolas living in the Annamite Mountains, but each group is isolated from the others in non-contiguous habitats. This kind of habitat fragmentation can erode a species’ genetic diversity and make it less resilient to additional dangers, such as hunting, disease, or climate change.

Although there is still enough potential saola habitat in Laos and Vietnam to support a larger saola population, the IUCN notes, that would require a significant change in current trends. Not only are saolas trapped in pockets of habitat, but the region is experiencing a high growth rate in human populations, which will likely add to the pressures already fueling the saola’s decline.

Lack of Captive Breeding

Saolas have been taken into captivity about 20 times since 1992, and all have died shortly afterward, except for two that were released back into the wild. There are currently no captive saolas anywhere, and thus no backup for wild populations.

While some declining wildlife can cling to existence with help from captive breeding programs—sometimes even after the species has vanished from the wild, like the Hawaiian crow—the saola enjoys no such buffer. If a captive breeding program can’t be established before the last wild saolas fade away, the species will be lost forever.

What We Can Do

Saving the saola from extinction won’t be easy, but it does seem to still be technically possible. That might not sound like much, but by the standards of Earth’s current mass extinction event, it’s a basis for hope that shouldn’t be taken for granted.

The largest subpopulation of saolas likely has fewer than 50 individuals, according to the IUCN, and with the entire species possibly down to double digits, it may already be too late to save saolas in the wild. It’s still worth trying, of course: Even if there isn’t an undiscovered population hiding out there somewhere, there’s at least a chance the known survivors could prove more resilient than expected.

The saola needs safe, spacious, and interconnected habitats, which means not just giving it wildlife preserves to live in, but also enforcing conservation laws meant to protect it from people.

Saola preserves have been created in parts of their range, but saolas living there are not always well-protected, according to the IUCN. There may be ongoing risks from habitat loss or local bushmeat hunting, but the primary threat comes from snares set by poachers, who are typically seeking other animals to sell in the wildlife trade.

Even if this poaching threat could be stopped, however, wild saolas might still be doomed simply because there are now so few of them in such disjointed habitats. That’s why, aside from efforts to protect wild saolas, the species’ fate may hinge on the success of a planned captive-breeding program.

No saolas have ever survived long in captivity, which might not seem to bode well for this plan, although previous attempts to keep saolas in captivity have been less sophisticated than the kind of modern captive-breeding programs now in use for some other endangered species.

Maybe that kind of program really could save the saola, but in order to try, scientists will need to find—and safely capture—wild saolas. That’s a challenge with many wild animals, but it’s especially daunting for a species that’s never even been seen in the wild by a biologist.

So before any captive breeding can begin, scientists are first working on ways to find saolas, such as setting up camera traps, interviewing local people, and even searching for saola blood in leeches collected from Annamite forests.

This search remains the top priority, according to the IUCN’s 2020 Strategy and Action Plan for Saola Conservation, which notes there are still some newer detection methods that haven’t been tried with saolas. If any of these efforts pay off, the next challenge will be capturing those saolas and relocating them to a new captive-breeding center, where scientists will try to learn enough about this mysterious creature to help it reproduce in captivity.

Eventually, in a far-from-certain scenario in which all of this succeeds, the ultimate goal would be to reintroduce captive-bred saolas to the wild.

Save the Saola

• Don’t participate in the wildlife trade. That may not even seem like an option if you live far away, but the world is smaller than it used to be. Whether you’re shopping online or in a market closer to where wild saolas live, avoid buying anything that supports the trade of wild animal parts. Even if didn’t come from a saola, its sale could support the indiscriminate trapping that does kill saolas.
• Contribute to the Saola Conservation Fund, which is managed by the conservation nonprofit group Re:Wild under the guidance of the IUCN Saola Working Group. Donations to the Saola Conservation Fund go toward saola conservation projects in Vietnam and Laos.
• Help raise awareness. The saola is more endangered than many well-known animals, like elephants or tigers, yet relatively few people outside its home range even know it exists. Talk to your friends and family, and ask them if they know about saolas. Draw pictures of saolas with your kids, and talk about how cool it would be to see one in the wild. The fate of saolas likely rests with our species, so they need all the attention they can get.