The Asiatic wild ass is back where it belongs. After more than 65 years of absence, the endangered species — known locally as khulan (Equus hemionus) — has returned to eastern Mongolia and is showing clear signs of re-establishing a permanent population, the Wildlife Conservation Society (WCS) announced on May 1, 2026.
Researchers based in Ulaanbaatar confirmed the return after years of careful monitoring, calling it one of the most significant rewilding milestones on the Eurasian steppe in decades. The eastern grasslands had been considered functionally empty of khulan since the 1950s, when habitat fragmentation, hunting, and infrastructure development pushed the species into a single, isolated stronghold in southern Mongolia's Gobi Desert.
A Long Walk Home
Khulan are some of the most mobile large mammals on Earth. Individual animals routinely cover hundreds of kilometers in search of seasonal grazing, and herds can range across an area larger than many small countries. That mobility is what made the eastern recolonization possible — but only after barriers came down. WCS Mongolia has worked for more than a decade with the Ulaanbaatar Railroad Authority and the Mongolian Academy of Sciences to identify and modify the fences, roads, and rail corridors that had effectively walled the species off from its historical range.
"This is an event that should be heard around the world," WCS researchers said in announcing the return. "Khulan are ecosystem engineers. When they come back, the steppe comes back with them."
Why It Matters
The Asiatic wild ass is listed as endangered on the IUCN Red List. Global numbers have declined by more than half over the past two decades, with Mongolia holding roughly 80% of the world's remaining population. A second, self-sustaining herd in the country's east effectively doubles the species' geographic safety net — a critical hedge against drought, disease, and human pressure on the Gobi population.
Khulan also play an outsized ecological role. Their grazing patterns shape grass communities, their dust baths create microhabitats for invertebrates and small mammals, and their long-distance movements help disperse seeds across thousands of square kilometers of steppe. Saiga antelope, Mongolian gazelles, and steppe-nesting birds all benefit from a landscape that includes khulan.
What Comes Next
Conservationists say the focus now shifts from documenting the return to protecting it. That means keeping wildlife corridors open as Mongolia's mining and rail networks continue to expand, working with herder communities who share the steppe with the returning animals, and tracking the new herd's reproductive success over the coming seasons. WCS is also using GPS collars on a small number of animals to map exactly which routes the khulan are using to travel between the south and the east — information that will guide future infrastructure planning.
"You can't bring a species back to a landscape if the landscape itself is broken," one WCS biologist noted. "What we're seeing in eastern Mongolia is proof that, when you give a wild animal a fair chance, it knows how to find its way home."
For Mongolia's vast, open steppe — one of the last great grassland ecosystems on the planet — the return of the khulan after 65 years is more than a conservation win. It's a reminder that empty places can fill back up.
