First aid (wilderness first aid in particular) can help a person survive and function with injuries and illnesses that would otherwise kill or incapacitate him/her. Common and dangerous injuries include:
The survivor may need to apply the contents of a first aid kit or, if possessing the required knowledge, naturally occurring medicinal plants, immobilize injured limbs, or even transport incapacitated comrades.
A shelter can range from a “natural shelter”; such as a cave or a fallen-down tree, to an intermediate form of man-made sheltersuch as a debris hut, a tree pit shelter, or a snow cave, to completely man-made structures such as a tarp, tent, or a longhouse.
Making fire is recognized in the sources as significantly increasing the ability to survive physically and mentally. Lighting a fire without a lighter or matches, e.g. 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. Producing fire under adverse conditions has been made much easier by the introduction of tools such as the solar spark lighter and the fire piston.
If you have a black powder firearm along, you can sometimes start a fire by ramming tinder down the barrel against the powder charge. Use charred cloth if available. Fire the gun up in the air, run and pick up the cloth and blow it into flame. Have a supply of tinder at hand so the cloth can be placed against it to start the fire.
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 a survivor, however wild animals may be attracted to the light and heat of a fire.
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
A typical person will lose minimally two to maximally four liters of water per day under ordinary conditions, and more in hot, dry, or cold weather. Four to six liters 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 does not recommend drinking water only when thirsty, as this leads to under hydrating. Instead, water should be drunk at regular intervals. 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.
Recent thinking is that boiling or commercial filters are significantly safer than use of chemicals, with the exception of chlorine dioxide.
Focusing on survival until rescued by presumed searchers, the Boy Scouts of America especially discourages foraging for wild foods on the grounds that the knowledge and skills needed are unlikely to be possessed by those finding themselves in a wilderness survival situation, making the risks (including use of energy) outweigh the benefits.
These two pictures of the same tree trunk in the Northern Hemisphere are an example of a navigational terrain feature. The left picture shows the northern side of a trunk, where darker and more humid micro climatic conditions favor moss growth. The right picture is south, with sunnier and drier conditions, less favorable for moss growth. The shady side is not always opposite the noon side.
Survival situations can often be resolved by finding a way to safety, or a more suitable location to wait for rescue. Types of navigation include:
Celestial navigation, using the sun and the night sky to locate the cardinal directions and to maintain course of travel
Natural navigation, using the condition of surrounding natural objects (i.e. moss on a tree, snow on a hill, direction of running water, etc.)
The mind and its processes are critical to survival. The will to live in a life and death situation often separates those that live and those that do not. Stories of heroic feats of survival by regular people with little or no training but a strong will to live are not uncommon. Among them is Juliane Koepcke, who was the sole survivor among the 93 passengers when herplane crashed in the jungle of Peru. Situations can be stressful to the level that even trained experts may be mentally affected. One should be mentally and physically tough during a disaster.
To the extent that stress results from testing human limits, the benefits of learning to function under stress and determining those limits may outweigh the downside of stress. There are certain strategies and mental tools that can help people cope better in a survival situation, including focusing on manageable tasks, having a Plan B available and recognizing denial.
Often survival practitioners will carry with them a “survival kit”. This consists of various items they seem necessary or useful for short durations in the wilderness. Supplies in a survival kit normally contain items like a sharp knife (such as a Swiss Army Knife), matches, a first aid kit, fish hooks, a sewing kit and an LED flashlight. Often these items will have multiple possible uses as space and weight are often at a premium.
Some survival books promote the “Universal Edibility Test”. Allegedly, it is possible to 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 experts including Ray Mears and John Kallasreject this method, stating that even a small amount of some “potential foods” can cause physical discomfort, illness, or death.
Many mainstream survival experts have perpetuated the act of drinking urine in times of dehydration. However, the United States Air Force Survival Manual (AF 64-4) instructs that this technique should never be applied. Several reasons include the high salt content of urine, potential contaminants, and sometimes bacteria growth, despite urine’s being generally “sterile“.
Many classic cowboy movies and even classic survival books suggest that sucking the venom out of a snake bite by mouth is an appropriate treatment. However, once the venom is injected into the blood stream, it cannot be sucked out and it may be dangerous to attempt to do so. If bitten by a venomous snake, the best chance of survival is to get to a hospital for treatment as quickly as possible.