As someone has said, soft tissue is usually the first to be scavanged which explains the tongue being missing.
Regardless, something caused them to leave their tents. It could have been a wild animal or even the sound of an avalanche that, perhaps, didn't reach them. They only had to be afraid of getting trapped in the middle of the night, awakened by a rumble to make them rush out of the tent as quickly as possible. I know that when I'm awakened suddenly by something scary, I am extremely confused for a long while after. Hypothermia only exacerbates the confusion.
Also from the article posted. " It happened on the east shoulder of the mountain Kholat Syakhl (Холат Сяхл) (a Mansi name, meaning Mountain of the Dead)." Apparently, the mountain is dangerous. People don't name things the Mountain of the Dead because the grass is sweet and daisies grow in the wake of pretty fairies.
Or, yeah, it's a magical flying hyrax back from hibernation to avenge the death of his brothers at the hands of socialist Russia. It's 50/50.












