A BBC TV crew witnessed the death of 150,000 Antelope over the space of three days while filming Planet Earth II.
A member of the film crew said they journeyed deep into the plains of Kazakhstan in Central Asia to find the calving grounds of the Saiga Antelope, only to see thousands of them succumb to disease.
Chadden Hunter, producer of the Grasslands episode, said thousands of the animals were giving birth when a virulent disease hit the population wiping out 150,000 in days.
He told the paper that the TV crew believed they were witnessing the extinction of the species.
He said: “At the time we thought we were watching the greatest natural catastrophe that I’d ever heard of.
“We watched 150,000 of these magnificent animals die in front of us.
“At the time we didn’t know if it was the final extinction of the species, which was devastating for the crew.”
It was later established that, despite the mass deaths, there are still Saiga Antelope in the wild.
Viewers tuning into the hit BBC programme on Sunday will see footage of the animals on the planes of Kazakhstan.
Planet Earth II has seen soaring audience numbers, with 9.7 million viewers tuning in to watch last week’s episode.