Bacteria played a role in the recent saiga deaths, according to Live Science, but the exact cause is still unknown.
Massive die-offs have struck saigas before, such as one that took the lives of 12,000 last year, but this one was unprecedented.
"The extent of this die-off, and the speed it had, by spreading throughout the whole calving herd and killing all the animals, this has not been observed for any other species," Zuther told Live Science.
For now, there are still thousands of healthy saigas in the world, but they are still an endangered species - thankfully, scientists will continue to investigate the specific cause of saiga deaths. Hopefully, they'll find the answer soon.