(CNN) -- Environmentalists in Vietnam were ebullient this week after remote cameras in a forest reserve snapped pictures of a live saola, one of the rarest large mammals on Earth.
At most a few hundred -- and as few as a couple dozen -- of the animals are thought to exist. Because of that rarity and its elusiveness, the saola is dubbed the "Asian unicorn." That moniker comes despite the fact it has two closely spaced parallel horns.
"These are the most important wild animal photographs taken in Asia, and perhaps the world, in at least the past decade," said William Robichaud, coordinator of the Saola Working Group of the International Union for Conservation of Nature's Species Survival Commission, in a World Wildlife Fund press release.
"This is an historic moment in Vietnam's efforts to protect our extraordinary biodiversity," Dang Dinh Nguyen, deputy head of the country's Quang Nam Forest Protection Department, said in the release.
The picture of the animal was taken in September in a reserve in the Central Annamite Mountains and announced by the WWF on Tuesday.
Van Ngoc Thinh, WWF-Vietnam's country director, called the picture "a breath-taking discovery."
"When our team first looked at the photos we couldn't believe our eyes. Saola are the holy grail for Southeast Asian conservationists," Van said in a press release.
The saola, which is a relative of cattle but looks like an antelope, was first discovered in 1992 in forests along the Vietnam-Laos border. A WWF survey team found a skull of the animal in a hunter's home. In Vietnam, a saola was last seen in the wild in 1998. In Laos, a remote camera snapped a picture of one in the wild in 1999. And in 2010, Laotian villagers captured a saola that died before word got to researchers.
There are no saola in captivity.
Environmentalists said Wednesday the pictures show that efforts to save the saola are working.
"Saola are caught in wire snares set by hunters to catch other animals, such as deer and civets, which are largely destined for the lucrative illegal wildlife trade," Van said in the WWF release. "Since 2011, forest guard patrols ... have removed more than 30,000 snares from this critical saola habitat and destroyed more than 600 illegal hunters' camps."