We Don’t Know Yet Why 200,000 Antelopes Died In The Span Of Just A Few Weeks

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It’s been a very bad year for the saiga antelope.

More than 200,000 saigas — a small, critically endangered species of antelope with a distinctive snout — died this spring — a number that’s more than half of the antelope’s entire population. Scientists aren’t yet sure exactly why the species is dying off in such huge numbers, but as the New York Times reports this week, climate change might be contributing.

Saigas, which live in Central Asia, carry bacteria called pasteurella in their throats. Usually, the bacteria is harmless, but scientists told the New York Times that unusually stormy weather this spring — complete with high winds and temperature drops — may have weakened the animals enough that the pasteurella ended up killing them. In the spring, the saigas would have just lost their winter coats, and the scientists say that climate change has raised May temperatures in the saigas’ habitat a few degrees over the last few decades, so a sudden, severe temperature drop could be dangerous for the antelope.

Though the bacterial infections are a likely cause of — or at least contributor to — the saiga deaths, there are still questions surrounding the die-off, which occurred only among a population of saigas in Kazakhstan. One scientist noted in June that Saigas are moving farther north now than they have historically, so different pastures could carry different dangers. Heavy rainfall could also be dangerous, as well as disease transmission from livestock. Saigas have also experienced other mass die-offs in the past, so scientists are looking into these to see whether they hold clues for this year’s die-off.

Saigas used to be common in Central Asia, but hunting for their meat and horns whittled their numbers down to about 81,000 in 2010. Their numbers have grown since then, but die-offs — blamed largely on pasteurellosis, an infection that comes from the pasteurella bacteria — have knocked them down a few times.

“It’s a question of luck at this stage,” Richard Kock from the Royal Veterinary College at the University of London told the Guardian of the species’ survival chances. “If you can lose 100 percent of a population, you’re left with a few populations and they are all affected at the same time, that’s it … If climate change is involved, the frequency [of deaths] will increase and if that’s the case then extinction could be inevitable.”

The cause of the saigas’ die-off may still be uncertain, but climate change has been known to affect other animals. Heavy rains, which have become more common as the climate warms, have killed peregrine falcon chicks in the Arctic. Arctic tern chicks have starved to death in Maine as warming oceans shift fish to cooler waters. And melting sea ice has caused walruses to converge on Alaska beaches by the thousands, a gathering which can lead to death by trampling.