A shelter can protect you from the sun, insects, wind, rain, snow, hot or
cold temperatures, and enemy observation. It can give you a feeling of
well-being and help you maintain your will to survive.
In some areas, your need for shelter may take precedence over your need
for food and possibly even your need for water. For example, prolonged
exposure to cold can cause excessive fatigue and weakness (exhaustion). An
exhausted person may develop a "passive" outlook, thereby losing
the will to survive.
Seek natural shelters or alter them to meet your needs, therefore, saving
energy. A common error in making a shelter is to make it too large. A
shelter must be large enough to protect you and small enough to contain your
body heat, especially in cold climates.