Survival Rule

Rule of three

Human survival priorities are found in the "Rule of Three":

  1. Humans cannot survive more than three minutes without air (O2)
  2. Humans cannot survive more than three hours exposed to extreme low-temperature
  3. Humans cannot survive more than three days without water (H20)
  4. Humans cannot survive more than three weeks without food
The Rule of Three should be viewed as generalities. The record is 10 minutes, 17 seconds without air, the crew of a boat lasted 8 days without water; people have survived without food for over 40 days.

In most survival situations, three priorities must be addressed before any other needs are met:
  1. Finding or making shelter is the most important because it allows a person to stay protected from the elements.
  2. The next priority after finding shelter is water. The length of survival mostly depends upon climate conditions and physical exertion.
  3. Food is the third essential for survival. This is especially important during winter, as one has higher calorie-burning needs.

These priorities may change depending upon environmental factors.

A shelter will protect one from potentially disastrous weather, help prevent hypothermia, and allow restful sleep. It will also boost how you feel emotionally, as it will become a base or home. Therefore, in typical survival situations, a shelter should be able to be moved with you, if possible, and be set up quickly. If one spends too much time on a shelter it takes away from other survival tasks.

A shelter should provide a somewhat comfortable place to sleep. To this end, it should account for the following:

  • Immovable rocks, animal nests, and other obstacles and hazards should be avoided.
  • Dry watercourses may be flat, sandy, and comfortable to sleep on, but they will flood in a storm.
  • Sunlight provides warmth (which is not always welcome), and help one to wake up in the morning. However, sunny, open areas are vulnerable to wind.
  • Heat transfer: an excessively large or well-ventilated shelter will not retain warmth well.
  • Flashing (weatherproofing) to provide protection from elements.
  • A cave would be a very useful shelter because it is very resistant to rain water getting in and maintains a constant temperature. Unfortunately, caves can present additional problems such as ground water, dampness and wildlife. Bears also nest in caves, so before selecting a cave to stay in, you should check it for signs of inhabitance.

The simplest and most mobile shelter is a tarp, supported by make-shift frame work or rope. Large leaves, such as ferns or fir branches, can be added to a latticework of branches. Ferns on a shelter provide insect repellent. Branches propped against a fallen tree make a simple and effective refuge, but animals such as ants and snakes may nest under the tree. With some practice, more advanced shelters such as a debris shelter can be constructed without modern tools or implements.


A human can survive a maximum of three days without the intake of water, assuming you are at sea level, at room temperature, and a relative humidity.

In colder temperatures and/or with rain or snow the length or likelihood of survival would be greatly reduced. In addition to the aforementioned priorities, length of survival also depends on amount of physical exertion. A typical person will lose 2-3 liters of water per day in ordinary conditions, but more in hot, dry, or cold weather.

A lack of water causes dehydration, resulting 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. Your body requires 4L to 6L of water or other liquids each day in the wilderness to avoid dehydration and to keep your body functioning properly.

Dark yellow or brown urine indicates dehydration. Because of these risks, a safe supply of drinking water must be located as soon as a shelter is built (or even before, depending on conditions).

Water can be gathered in numerous ways: scooped out of a creek or pond; rainwater can be caught in makeshift containers; collect dew from vegetation in clothing articles. Many tree roots and vines contain water. The cactus is also a source of water, confirming the myth- pulp can be removed from the broken stem.

In a survival situation, any water supply may be contaminated with pollutants or pathogens (see Potability of back country water). Although little can be done to remove molecular contaminants, particles and microorganisms can be removed and/or killed (see Portable water purification). In a beach situation, digging in the sand below sea level, the sand well will fill with drinkable water; it may taste salty or brackish, but the sand acts as a filter reducing the salt content the further you dig inland. Stagnant water can be made drinkable by filtration through a sieve of charcoal.

Animal blood is not suitable for re hydration as it may be diseased. In addition, because of the nutrients it contains, it requires energy to digest. Mammals all have blood-borne pathogens so the animal must also be cooked. Urine contains salt and other toxins, which also makes it unsuitable to drink, although it can be refined in a solar still.

Many birds, mammals, and some insects, such as bees, ants, and mason flies, are reliable indications of water, either through a stream or a soaked patch of earth.

The U.S. Army survival manual recommends that you use your water whenever thirsty to avoid "voluntary" dehydration. Other groups recommend rationing water through "water discipline".

While finding water is most important, preventing water loss is also an issue. Resting, avoiding smoking, and breathing through the nose are recommended.


A fire is as important as a safe water supply, because of its many uses:

  • Boiling water to kill pathogens (see above)
  • Cooking food, including wild-caught fish and game (see below)
  • Staying warm, particularly when wet
  • Repelling dangerous animals and certain insects (e.g. mosquitoes)
  • Provides a sense of companionship and morale boost
  • Signaling to rescuers (bright at night, smoky by day)

The area chosen should be flat and dry, with protection from wind.


Food is not urgently needed in survival situations, since a human can survive for several weeks without it. However, much like dehydration, hunger can bring about many consequences long before it causes death, such as:

  • Irritability and low morale
  • Weakness
  • Loss of mental clarity, such as confusion, disorientation, or poor judgment
  • Weakened immune system
  • Difficulty maintaining body temperature

It is actually rather easy to find food in most wild environments, provided one knows where to look. A basic knowledge of animal trapping, hunting, and fishing will provide meat. Equally important is a knowledge of edible plants, fungi, and lichens. One cannot always rely on the most abundant or most easily accessible type of food. To survive for long periods of time, one must maintain a balanced diet. In order to do this, one must consume a balanced variety of foods.

Many survival books promote the "Universal Edibility Test": allegedly, one can distinguish edible foods from toxic ones by a series of progressive exposures to skin and mouth prior to ingestion with waiting periods and checks for symptoms. However, many other experts reject this method, in main part because a very small amount of some "potential foods" can cause anything from gastric distress to illness or death. An additional step called the "scratch test" is sometimes included. In this step (before mouth contact of the proposed food) one makes an abrasion on the surface of an area of skin (such as with fingernails) and then lightly rubs some of the food product on the abrasion. Foods that cause surface inflammation, discomfort, itching or eruption should be avoided.

Finding food in the wild depends on your environment (i.e. vegetation, animals, and water sources).

First aid

First aid (wilderness first aid in particular) can help a person survive and function with injuries that would otherwise kill or incapacitate him/her. Common and dangerous injuries include:

  • Lacerations, which may be infected
  • Bites from venomous animals, such as snakes
  • Bone fractures
  • Sprains, particularly of the ankle
  • Burns

The survivor may need to apply the contents of a first aid kit or naturally-occurring medicinal plants, immobilize injured limbs, or even transport incapacitated comrades.


Survival situations are resolved by finding one's way to safety. This requires some navigation or movement:

  • Celestial navigation, using the sun and the night sky
  • Reading a map (particularly a topographic map), together with a compass
  • Using a GPS receiver, if one is available

Other survival skills

For long-term survival some other skills are useful:

  • Knife or Multitool - usage and sharpening (a knife or Multitool is very important for all survival situations and for many aspects of bushcraft)

A sheath knife of high carbon steel with a 4 to 6 inch blade is invaluable for the creation of tools, splitting wood for fire building using a baton, building shelters and many other skills.

  • Climbing and Mountaineering techniques
  • Ropework
    • Making rope from materials such as the inner bark of trees, other plant fibers, or animal sinews
    • Knowledge of knots and their applications
  • Making a raft or boat
  • Weapons are an essential part of a large survival outfit. Weapons protect you and those around you and allow you to procure food through hunting. There are many points of view on this issue but by and large, a good 22 long rifle will serve to procure game and provide for moderate protection from predators both the four legged and two legged variety.
  • Be sure to get proper training to be safe with firearms.
  • Basic primitive weapons can be important tools: they include spears, Vietnam crossbows, longbows, the throwing stick, clubs etc. Many primitive tools can also fill the weapon class as well such as a stone axe. First hand instruction is essential.


Survival Training has many components, mental competence and physical fitness being two. Mental competence includes the skills listed in this article, as well as the ability to overcome panic and think clearly. Physical fitness includes, among other abilities, carrying loads over long distances on rough terrain. Theoretical knowledge of survival skills is useful only if it can be applied effectively in the wilderness. Almost all Survival Skills are environment specific and require training in a particular environment.

Survival Training is broken down into three types, or schools; Modern Wilderness Survival, Bushcraft, and Primitive Survival Techniques. Modern Wilderness Survival teaches the skills needed to survive Short-Term (1 to 4 Days) and Medium-Term (4 to 40 Days) survival situations. Bushcraft is the combination of Modern Wilderness Survival and useful Primitive Survival Techniques. It normally splits its skill acquisition between Medium-Term Survival Techniques (4 to 40 Days) and Long-Term Survival Techniques (40 Days Plus).Primitive Survival Techniques teaches the skills need to survive over the Long-Term (40 days plus). Many primitive technology skills require much more practice and may be more environment specific.[12]

Several organizations offer wilderness survival training. Course ranges from one day to field courses lasting as long as a month. In addition to teaching survival techniques for conditions of limited food, water, and shelter, many organizations that teach bushcraft and Primitive Survival seek to engender appreciation and understanding of the lifestyles of pre-industrialized cultures.

There are several books that teach one how to survive in dangerous situations, and schools train children what to do in the event of an earthquake or fire. Some cities also have contingency plans in case of a major disaster, such as hurricanes or tornadoes.

Mental Preparedness

It should not be overlooked what the will to live means in a life and death situation. All of the training and tools in the world will prove of little or no consequence without the desire to live. Stories of heroic feats of survival by regular people with little or no training are not uncommon. Even with a strong understanding of the way we may be mentally affected, even a trained survival expert may feel the crushing effects of psychological strain during duress. In order to overcome these affects it is important to study stress and how it may affect us both good and bad.

Studying stress will reveal to us that while it may not always seem like it, stress is a necessary evil and belongs for not only for malice but good as well. It serves as a measuring stick for our success, it presents one with challenges, and it is a good way to show us how far we can bend and not break. Stress sometimes has a nice way of pointing out that things could indeed be much worse. On the flip side of the coin too much stress can be a awful thing. The carnage that stress can breed within a human being is almost without limits. Too much stress can lead to forgetfulness, increased propensity to making mistakes, lessened energy, outbursts of rage, and carelessness.

Emotions are hard wired into our DNA. Survival situations are bound to invoke strong emotional reactions from anyone evolved. There are a few emotions that most often accompany this type of event. They drastically lesson are ability to combat the situation. It is not something that initially comes to mind when thinking of surviving but they are as important as any other survival skill.

How To Create A Signal

Remember when you were a kid and your mom used to tell you, "If you go out, leave a note"? It wasn't because she was beìng nosey. Telling someone where you're goìng and when you expect to be back ìs a good habit to get ìnto - especially ìf you wìll be traveling outdoors.

Should you find yourself stranded ìn the outdoors, the key to your rescue ìs your ability to create good signals for potential rescuers to see. The first thìng you should do ìs light a fire. A large fire creates a signal ìn the daylight and darkness of night. At night, choose kindling for your fire tat does not create a lot of smoke. Create three fires ìn the outline of a triangle, because ìf these are seen from the air they wìll be recognized as the symbol for distress, and wìll be less likely to be mistaken for a simple campfire. When choosing the location for your fire, make sure ìt is an open location without a lot of foliage blocking the view. Also, have water on hand should the fire spread beyond your control. A raging forest fire would endanger your life and make rescue impossible.

If there ìs an isolated tree nearby, you can create a tree torch by setting ìt on fire. If ìt is a pitch-bearing tree, you simply have to ignite the tree. If ìt is not pitch bearing, pile dry kindling around the tree and ignite it. The kindling fire wìll spread to the foliage of the tree. Keep your tree torch burning by adding to ìt as ìt consumes the tree.

Where there's smoke, there's fire - and smoke could also mean someone who's lost or ìn trouble. During the daytime, when a fire itself mìght not be very visible, you want to add green kindling, leaves, or grass to your fire. Evergreen branches make for excellent smoke signals. Get the smoke to billow as high as you can; thìs will give you a better chance of a passerby seeing it.

Another way to signal for help ìs to signal to low-flying aircraft. Using a mirror reflecting the sunlight, you can flash the S-O-S symbol at low-flying aircraft. Avoid flashing the mirror directly at the cockpit, as that wìll cause the pilot to have difficulty seeing. At night or ìn times when there ìs not a lot of sunlight, the same affect can be accomplished using a strong flashlight. Always carry a flashlight and extra batteries when venturing outdoors.

If none of these techniques work, use brightly-colored clothing to attract attention. Hang a bright scarf or coat from the top of a high tree, or arrange clothing ìn a pattern on the ground to draw attention from the air. Do not leave yourself too vulnerable to the elements by removing too much clothing though. You can even create signals using natural materials, such as tree branches or rocks, that can be viewed from the air. Try spelling out S-O-S or HELP wìth rocks or branches. Remember to use a material that wìll stand ìn contrast to your surroundings. If there ìs snow on the ground, walk ìn the snow to form the letters, and fill ìn the path wìth dark material, lìke rocks or tree branches.

Be creative wìth the materials around you. Do anything you can to create something that looks out of the ordinary and wìll cause an observer to stop and take a closer look. Keep safety as your ultimate goal, though, and do not create a signal that wìll jeopardize your safety. Seek out food, water, and shelter, create a good signal, and help wìll soon be there!