New research finds clues about mass death of saigas
Back in late May, a group of dog-sized, steppe-dwelling antelope began dying en masse. By day four the entire herd of around 60,000 saiga was completely decimated. While mass die-offs like this one have happened before, this incident had the benefit of a large group of researchers and veterinarians at the scene who managed to uncover some clues as to the cause of the mysterious mass deaths.
Geoecologist Steffen Zuther and his colleagues were heading to Kazakhstan to monitor the calving of the saiga herd, but by the time they arrived veterinarians already at the scene were reporting deaths. LiveScience reported on September 2, that initially Zuther, an international coordinator at the Altyn Dala Conservation, and his team were not particularly concerned.
“But since there happened to be die-offs of limited extent during the last years, at first we were not really alarmed,” Zuther told LiveScience. As the number of deaths began to rise, Zuther and his team began to catalogue the event so that they could figure out precisely what was causing all of the deaths. The team began to hear of other mass die-offs occurring with herds across the country. “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,” said Zuther.
While no-one is quite sure how all the pieces of the mystery came together to cause such a rapid devastation of the herd, the team has gathered some clues as to what exactly happened. First, the team believes that bacteria likely had a large role, but the kind of microbe the team suspects is generally harmless, which begs the question of what happened to make this ordinary bacteria highly deadly.
Saigas, currently listed as critically endangered by the International Union for the Conservation of Nature, are strange looking creatures. About dog-sized, with giant odd-looking noses, saigas play an essential role in the ecology of the steppe, where they help break down organic matter and recycle nutrients that would otherwise be prevented from decomposing by the freezing cold winters.
Unlike last year, when 12,000 saiga perished in a mass die-off with no scientists near to catalogue the cause, a group of researchers were already on the ground this year and managed to take a massive number of samples from the saiga environment, including the soil they walked on and the water they drank. The scientists even managed to observe the behavior of the saiga as they perished, noting that the females went first, followed closely by the calves, suggesting that the deadly microbe was passed through the mother’s milk.
Samples taken from the tissue of dead saiga revealed toxins related to Clostridia and Pasteurella bacteria which caused a large amount of bleeding in the animals’ internal organs. The problem with this diagnosis is that the bacteria are ordinarily not deadly, so their presence doesn’t exactly solve the mystery.