Largest herd of gazelles sighted in Mongolia

A mega-herd of a quarter of a million Mongolian gazelles has been seen gathering on the country's steppes, one of the world's last great wildernesses.

The coming together on the grassy plains is the largest ever recorded.

The biologists who saw it estimate it contained perhaps a quarter of all Mongolian gazelles on the planet.

"It was stunning," says Kirk Olson of the University of Massachusetts, US. "I don't know if I was surprised or simply blown away by what we came across."