Let me address the first question of why you would need a survival shelter. When it comes to human survival, many people think of food and water first. Food and water are important, but if we look at the order of operations of the rules of three, in terms of their importance, they are as follows:
- You can survive for three minutes without air
- You can survive for three hours without shelter (maintaining core body temperature)
- You can survive for three days without water
- You can survive for three weeks without food
Barring any physical injury that restricts breathing, serious blood loss, or any serious health condition, exposure to the elements can lead to death quicker than lack of food or water.
It should be noted that shelter is not always necessary. As long as you can maintain core body temperature, then you will survive. For example, I have slept sitting against a tree overnight during favorable weather conditions.
