Survival skills are techniques a person may use in a dangerous situation (e.g. natural disasters) to save themselves or others (see also bushcraft). Generally speaking, these techniques are meant to provide the basic necessities for human life: water, food, shelter, habitat, and the need to think straight, to signal for help, to navigate safely, to avoid unpleasant interactions with animals and plants, and for first aid. In addition, survival skills are often basic ideas and abilities that ancient humans had to use for thousands of years, so these skills are partially a reenactment of history. Many of these skills are the ways to enjoy extended periods of time in remote places, or a way to thrive in nature. Some people use these skills to better appreciate nature and for recreation, not just survival. Shelter
Airmen of the United States Air Force construct a survival shelter during Arctic Survival Training in Alaska. Shelter is anything that protects a person from his/her environment, including dangerous cold and heat and allow restful sleep, another human need. A shelter can range from a "natural shelter"; such as a cave or a fallen-down (cracked but not split) thickly-foliaged tree, to an intermediate form of man-made shelter such as a debris shelter, a ditch dug next to a tree log and covered with foliage, or a snow cave, to completely man-made structures such as a tarp, tent, or house. Fire
Main article: Fire_making
Making fire is recognized in the sources as to significantly increase the ability to survive physically and mentally. Lighting a fire without a lighter or matches, such as by using natural flint and steel with tinder, is a frequent subject of both books on survival and in survival courses. There is an emphasis placed on practicing fire-making skills before venturing into the wilderness. Fire is presented as a tool meeting many survival needs. The heat provided by a fire warms the body, dries wet clothes, disinfects water, and cooks food. Not to be overlooked is the psychological boost and the sense of safety and protection it gives. In the wild, fire can provide a sensation of home, a focal point, in addition to being an essential energy source. Fire may deter wild animals from interfering with the survivor, however wild animals may be attracted to the light and heat of a fire. The light and smoke emitted by a fire can also be used to work at night and can signal rescue units. Water
A human being can survive an average of three to five days without the intake of water, assuming sea-level altitude, room temperature and favorable relative humidity. In colder or warmer temperatures, the need for water is greater. Need for water also increases with exercise. A typical person will lose minimally 2 to maximally 4 litres of water per day under ordinary conditions, and more in hot, dry, or cold weather. Four to six litres of water or other liquids are generally required each day in the wilderness to avoid dehydration and to keep the body functioning properly. The U.S. Army survival manual recommends that you drink water whenever thirsty. Other groups recommend rationing water through "water discipline". A lack of water causes dehydration, which may result in lethargy, headaches, dizziness, confusion, and eventually death. Even mild dehydration reduces endurance and impairs concentration, which is dangerous in a survival situation where clear thinking is essential. Dark yellow or brown urine is a diagnostic indicator of dehydration. To avoid dehydration, a high priority is typically assigned to locating a supply of drinking water and making provision to render that water as safe as possible. Many sources in survival literature, as well as forums and online references, list the ways in which water may be gathered and rendered safer for consumption in a survival situation, such as boiling, filtering, chemicals, solar radiation / heating (SODIS), and distillation (regular or via...