Scientists Offer Solution to Kazakhstan Saiga Deaths Puzzle
“It started with just a few and then gradually gathered pace over two or three days,” Kock explains. “The best description is that they were dying like flies. Eventually the landscape was completely littered with these animals…From moving and eating normally to death was just a matter of hours. So it was hopeless. We wouldn't have had a chance of doing much to help individuals.”
“The cause of death of the saigas is hemorrhagic septicemia,” Steffen Zuther, a German researcher and the international coordinator of the Astana-based Altyn Dala Conservation Initiative, told the TV channel. Hemorrhagic septicemia — which scientists believe was rapidly spread across the steppe by ticks in May — is a form of pasteurellosis, a disease that killed nearly 12,000 saigas in a 2010 epidemic.
According to Professor Richard Kock from the University of London, a latent bacteria already present in the antelope’s system is the most likely factor in their mass death. The pasteurella resides in the throat of the antelope and is general harmless. However, an unknown factor may have acted as a catalyst for the bacteria to turn malevolent and cause the deaths of the unfortunate animals within weeks of each other.
Professor Kock believes this is most likely due to an environmental factor. The temperatures in Kazakhstan plummeted from 30°C to a frosty -5°C in the days leading up to the deaths.
In addition to the hike in temperatures, the knock-on effect on soil and vegetation in the area could have triggered the pasteurella bacteria into action. Some evidence suggests these opportunistic bacteria can be temperature sensitive. If the temperature suddenly rises in the environment where the bacteria live, they can suddenly switch to virulence.
The saiga is a very unusual, ancient animal that predates the wooly mammoth. It is highly adapted to the extreme environment of the Central Asian steppe, where temperatures can range from 49 degrees below zero to 113 degrees. They migrate over huge distances. They are also one of the fastest hoofed animals on earth, capable of reaching speeds of up to 70 miles per hour.
As recently as 2014, the entire saiga population was about 300,000. The central group of about 250,000 is the key population, Kock says. When the die-off began, Kock and his colleagues monitored two additional population sites, one of about 60,000, another of 8,000. Gradually it became clear, however, that there were about 15 different die-off sites.
After the event, the Kazak government agreed to do a census to try to establish the mortality rate. They found that, at most, only 30,000 out of the 250,000 central population survived, Kock says.