When geocologist Steffan Zuther and his colleagues arrived in central Kazakhstant to monitor the calving of one heard of saigas, veterinarians in the area had already reported dead animals on the ground. WIthin four days, the entire herd—60,000 saiga—had died.
Now, the researchers have found clues as to how more than half of the country's herd, counted at 257,000 as of 2014, died so rapidly. Bacteria clearly played a role in the saigas' demise. But exactly how these normally harmless microbes could take such a toll is still a mystery, Zuther said.
"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 said. "It's really unheard of."