I have read that before, however, I think possibly, it is but one opinion:I went looking for the origin of the story of "quick-frozen mammoths"
Flash-Frozen Mammoths and Their Buttercups: Yet Another Case of Repetition and Recycling of Bad Data
The timing of the Post article was likely where LRH got the story from
Long but interesting article. Summary: scientifically illiterate reporter misinterprets data, writes article, and serves as a basis for misinformation for decades following.
Ancient stomach contents analyzed
The researchers also analyzed the stomach contents of well preserved carcasses of mammoths, woolly rhinos and ancient horses, as well as preserved feces. Those contained a similar variety of plants to the ones in the permafrost – mostly forbs.
Woolly mammoth discovery raises exciting possibilities
Froese said those had been barely detected before because those plants don't produce much pollen.
The DNA analysis also showed that the vegetation changed dramatically around 10,000 years ago, when the Arctic grew warmer and wetter, giving rise to the tundra we know today, dominated by grasses and woody plants.
"Most of the evidence we've been able to see is these large mammals disappear almost at the same time these vegetation changes were taking place," Froese said.
Meanwhile, there was a population explosion of animals that adapted to eating woody plants, such as moose, elk and caribou. Froese thinks they likely out-competed mammoths, rhinos and horses.