According to this book in 1823 General Ashley advertised for 100 men to ascend the Missouri to the Rocky Mountains. Hugh Glass was one of these men, signed on as a hunter for the expedition. Also on the expedition were two boys, Fitz Fitzpatrick and Jim Bridger.
Hugh Glass went hunting on his own, (against policy set by Ashley) found some ripe plums and started harvesting. He suddenly found himself face to face with a large Grizzly Sow with two cubs. The cubs were whining and hiding behind mom.
Hugh raised his rifle to kill her, she batted his rifle into the brush, he tried for his pistol, she swatted it away also. The fight was on, Hugh drew his skinning knife and saw immediately that while there was any distance between himself and the sow he was in trouble. He decided to close in and charged past her paws, hugged her with one hand and started sticking her in the belly with his knife. He struck many times, she chewed and bite him many times. She died from a heart thrust and fell on top of Hugh.
When he did not return to the Ashley party they went looking for him. He was so badly tore up they decided he would not live. Sewed him up and doctored him as much as they could. The party moved on, leaving the two boys, Fitz Fitzpatrick and Jim Bridger to stay with him until he died, bury him and rejoin the party.
Hostile Indians were in the vicinity, they got spooked, picked up his rifle, pistol, possible bag, knife and left him to join the Ashley party.
Hugh woke up, set his broken leg, or dislocated hip himself, made a travois so he could drag his leg with him and started crawling to the nearest fort. He was over 100 miles
away, but made it. This is quite a survival story, the content comes from many sources, but is considered very accurate.
This is probably one of the most dramatic and serious survival stories I have read.