Unlike most animals, we aren't naturally equipped to handle bad, extreme, or changing weather efficiently, nor to remain duly concealed/protected from predators and other threats. That's why knowing how to build a shelter in a variety of environments is so important.

I'm not talking just about rain, sun, heat and cold, people or wild animals: even insects and bugs can foist absolute hell. Outdoors, we are at risk and invariably suffer. Perishing becomes just a matter of time, depending on the fluidity of conditions.

Our gear and resources can also get lost or degrade rather quickly if not protected: food spoil, drinks get contaminated, stuff damaged, carried (or taken) away, and so on. Therefore, being properly sheltered is perhaps one of the most critical and defining situations in a person's life. It's certainly so during emergencies and evasions.

Building shelter is an essential skill.