It started in late May. When geoecologist Steffen Zuther and his colleagues arrived in central Kazakhstan to monitor the calving of one herd of saigas, a critically endangered, steppe-dwelling antelope, veterinarians in the area had already reported dead animals on the ground. “But since there happened to be die-offs of limited extent during the last years, at first we were not really alarmed,” Zuther, the international coordinator of the Altyn Dala Conservation Initiative, told Live Science.