During the last Ice Age, a vast grassland stretched from eastern Europe across Asia and into Alaska. Mammoths grazed it. So did woolly rhinos. And so did a small antelope with a swollen, drooping nose, the saiga (Saiga tatarica).

The mammoths and woolly rhinos are gone. The saiga is still here, in roughly the same form. It lives on the Central Asian steppe, the flat, open plains that cover much of Kazakhstan and reach into Russia, Uzbekistan and Mongolia.

A saiga is about the size of a sheep. Males average around 41 kilograms (90 pounds) and females around 28 kilograms (62 pounds). Only males grow horns, pale amber and ridged, about 15 to 25 centimeters (6 to 10 inches) long. The coat changes with the seasons, short and cinnamon brown in summer and thick and pale in winter, often almost white against the snow.

The steppe swings between extremes. Winter can drop to around −40°C (−40°F) and summer can climb past 40°C (104°F). In winter, the saiga's nose works like a radiator, warming frigid air before it reaches the lungs. In summer, it cools the air it breathes and filters out the dust kicked up by thousands of animals moving together across dry ground. Males also use it during the breeding season, when it helps shape the low calls they make to attract females.

In the early 1990s, there were an estimated one million saiga across Russia and Central Asia. By 2003, about 6 percent of them remained.

The crash followed the breakup of the Soviet Union, which left the saiga's range with little law enforcement and a great deal of rural poverty. Saiga horn is used in traditional Chinese medicine, and poaching exploded to supply that market.

Because only males carry horns, poachers took males. In some populations, the ratio fell to roughly one adult male for every hundred females, far too few to breed with them all. Birth rates collapsed.

Kazakhstan banned saiga hunting in 1999, but poaching carried on until the mid-2000s, when the government teamed up with conservation groups to put rangers on the steppe and crack down on horn smuggling. With the poachers held back, the saiga bred quickly. By 2014, Kazakhstan had around 257,000.

Every spring, female saiga gather in huge herds to give birth. In May 2015, the calving herds in central Kazakhstan started dying.

It began around May 10, and within days the same thing was happening in other calving herds across the region. In about three weeks, roughly 200,000 saiga were dead, more than 60 percent of the entire global population.

The cause turned out to be a bacterium called Pasteurella multocida. It normally lives in healthy saiga, including in their tonsils, without causing disease. In 2015, it invaded the animals' bloodstreams and caused hemorrhagic septicemia, a blood infection that leads to massive internal bleeding.

What triggered it was the weather. Researchers found the days before the die-off were unusually warm and humid, and they found the same kind of weather before two earlier mass deaths in the same region in the 1980s. Somehow those conditions turned a bacterium the saiga had always carried into something lethal. Scientists have described die-offs on this scale as unprecedented in any other large land mammal.

The recovery after 2015 is one of the fastest in modern conservation. Kazakhstan kept expanding its protection, adding border controls and new protected areas that now cover more than 5 million hectares (about 12 million acres). And left alone, saiga breed quickly.

In December 2023, the IUCN, the International Union for Conservation of Nature, moved the saiga from Critically Endangered to Near Threatened. That skipped two categories entirely, which almost never happens. At the time, Kazakhstan's population was estimated at more than 1.9 million, up from fewer than 50,000 in 2005.

Then the numbers kept climbing, and the story turned.

Farmers in western Kazakhstan began complaining that huge herds were eating their crops and competing with livestock for water and grazing land. The government's ecology ministry put agricultural damage in 2022 at about $25.5 million, a figure some conservationists doubted. A cull was announced, then suspended in February 2024 after the ministry consulted scientists. That April, President Tokayev called the saiga a symbol of the Kazakh steppe and said he wanted culling banned.

It came back anyway. Between July and November 2025, according to Kazakhstan's government, about 196,000 saiga were removed from the wild and sent to meat processing plants, with the horns collected and stored by the state. The ministry now puts the population at around 4 million.

So the saiga's recent history runs in both directions at once. It went from a million to near collapse, back to hundreds of thousands, lost most of them in three weeks, recovered to millions, and is now being culled for succeeding. The bacterium is still there in the tonsils, and nobody can predict the next warm, humid May.