Saigas, a critically endangered species of bulb nosed antelopes, found in Eurasian Steppes mysteriously died in unbelievably huge numbers within a short span of four days earlier this year. The unexplained calamity which struck the hapless animals wiped off almost half their total population, as the toll touched 120,000 in all. Scientists now believe this might be the most significant mass death event among the species.
Natives of Kazakhstan, Mongolia and Russia, these animals were once numbered in millions. Owing to unexplained and massive die-offs among the species in the past, their count was a rather worrisome 257,000 in 2014.
As 60,000 of them dropped dead within four days in central Kazakhstan this May, scientists, conservationists and veterinarians across the globe were horrified.
“I have worked in veterinary diseases all my career and I have never seen 100 percent mortality [within a herd],” Richard Kock, a wildlife veterinarian at the Royal Veterinary College in the U.K., remarked in June. “That is extraordinary.”
Added Steffen Zuther, geo-ecologist and international coordinator for Kazakhstan’s Altyn Dala Conservation Initiative, “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. It’s really unheard of.”
Scientists looking into these unprecedented deaths are now beginning to get first clues of the reason behind this catastrophe. Initial reports hold a bacteria which is normally considered harmless as the prime suspect. What made these seemingly benign micro-organisms trigger off such a die-off is not yet known for sure.
Researchers who observe these animals closely also suggest a pattern which these deaths followed. Female saigas which calve their young ones in clusters died first. Their little ones who were too young to live off vegetation alone soon followed suit.
Tissues samples collected from carcasses of dead animals reveal that their death was caused by extensive internal bleeding, effectuated by toxins produced by Pasteurella and perhaps the Clostridia bacteria. The former is normally found in saigas’ bodies without causing them any harm unless their immune systems are too weak.
Since herds staying hundreds of miles apart were wiped out at the same time, it is being suggested that environmental factors like cold winters and wet springs might have caused the bacteria to spread to all the animals so rapidly.