Survival skills are techniques a person may use for an indefinite duration in order to survive a dangerous situation (also see bushcraft). Generally speaking, these techniques are meant to provide the basic necessities for human life: fire, water, food, shelter, habitat, and the needs 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.
Such skills are presented as useful in situations such as storms or earthquakes or in dangerous locations such as desert, mountains, and jungle. Every different situation or location is said to present a different range of dangers - (see hazards of outdoor activities). Techniques to fit most situations are suggested by sources on the topic.
Secondary sources on survival skills, including those produced by the United States Army, and the Boy Scouts of America (priorities for an individual or group in a survival situation) , formulate lists of needs to be met in order to survive.
The needs for survival are differently conceptualized between sources; they may give six, or seven, or ten "needs" or "priorities." Furthermore, those sources often differ as to the relative priority of survival needs in a given survival situation. Some sources expressly acknowledge what seems manifest: that the order of priority of survival needs shifts according to the immediate situation faced.
One widely circulated concept to help set priorities is called the "Rule of Three": Employed a mnemonic device, the Rule of Three states:
1. Humans cannot survive more than three hours exposed to extreme low-temperature.
2. Humans cannot survive more than three days without water.
3. Humans cannot survive more than three weeks without food.
The Rule of Three is often otherwise formulated and is viewed by commentators as a rough guide. An aircrew reportedly lasted 8 days without water in a liferaft . People have survived without food for over twenty-one days.
The Boy Scouts, in addition to listing seven priorities, use a mnemonic device, "STOP", to address the mental aspects of survival. "STOP" stands for "Stop, Think, Observe, Plan."