Lawrence winter.

But it is better than no shelter, and combined with bear skins and a fire — fire, presumably made using the materials they had brought or whatever natural materials were available — it may have been enough.

The psychological dimension of survival over two and a half years is at least as important as the physical.

Research on long-term isolation — from accounts of castaways, prisoners in solitary confinement, and subjects of isolation experiments — consistently shows that the human mind requires some form of structure and purpose to maintain functioning.

The religious practice that the accounts mention — the daily reading of the Bible, the prayers, the maintenance of a spiritual framework — would have provided exactly this.