Scientists finally think they know what killed 211,000 of these antelope in May

An increasingly rare species of antelope called the saiga may be roaming its last days in the wild.

Native to the grassy steppes of Kazakhstan and nearby regions, populations of the critically endangered species have suffered one catastrophic loss after the next over the past 15 years.

And now, a mass die-off in the spring of 2015 seems to have killed off about half the species, according to The New York Times.

"I've worked in wildlife disease all my life, and I thought I'd seen some pretty grim things," Richard A. Kock, of the Royal Veterinary College in London, told the Times' Carl Zimmer. "But this takes the biscuit."

Scientists have narrowed down the possible causes of the die-off. And, according to Zimmer, unusual rain conditions caused by climate change turned a normal bacteria that lives in the Saiga's stomachs deadly.

Keep scrolling to learn more about the majestic animals - and what might be causing their imminent extinction.