This may seem overly simplistic, but if any of us are going to survive, we must have a basic knowledge of what we need to do in order to survive. That means having an understanding of what will kill us (if we don’t take care of it). Ask the average person on the street what those things are, and the answers you get probably won’t have anything to do with real survival.
That’s because, as a society, we’re far removed from the basic needs of survival. Those needs are met in ways that are sufficiently under the radar that we’ve pretty much forgotten what they are. Our concerns… or better yet “first world concerns” are over much more esoteric things that the basic needs to survive. About the best that most people can tell you if you ask them what’s needed in order to survive, is “food, clothing and shelter.”
But that phrase isn’t quite true. It originates from the scientific study of archaeology and anthropology, where scientists were seeking to understand how ancient man survived. As they sifted through the artifacts left behind by those ancient people, the top three things they looked for (to judge the group’s ability to survive in their environment), were how they procured food, made clothing and what they used for shelter. They didn’t look for water, because mankind was always forced by necessity to live near water.
This idea is great from an archaeological point of view, but it is worthless as advice for surviving. For one thing, it leaves water totally out of the picture. Try and live a few days without water, especially in a hot climate, and you’ll gain a very real understanding of how important water is. For another thing, it does nothing to explain why those three items are important. While the need for food is obvious, it’s not quite so obvious why we need clothing and shelter in order to survive.
So, if “food, clothing and shelter” aren’t the basic survival needs, what are?
Survival Priorities and the Rule of 3s
In order to survive, we must understand what our survival priorities are. By that, I mean we need to know which things are necessary in order to survive and understand their relative importance to each other. If any of us are ever caught in a do-or-die survival situation and spend all our time on things which are not critical to our survival – well, the chances are we won’t survive.
Take breathing, for example. If we are trapped underwater, without any air, whether or not we have any food isn’t our priority. We’re going to need to find some way of getting air long before we need to eat – even if we’re starving. So breathing is a higher priority than eating. This might seem obvious at first, but in real situations it may not be. For example, if you’re caught in some kind of end-of-the-world pandemic killer flu or viral outbreak, would you be aware of the fact that getting your hands on a gas/chemical mask (to avoid getting the flu) is a higher priority than locating food or water? (learn what other things you need to survive a pandemic here) If the air you breathe compromised, then finding a way to ‘produce’ or ‘filter’ the air should be your first priority.
We can list the top survival priorities using what is known as the Rule of 3s. It says, you can live:
- 3 minutes without oxygen [1]
- 30 minutes without maintaining your body temperature
- 3 days without water
- 30 days without food
Keep in mind that those numbers are not absolutes. A lot depends on the individual’s physical condition and health, as well as environmental conditions. You may not be able to survive as long as three days without water if you are in a hot climate, where your body is losing a lot of water through perspiration.
The point is that even though these are not absolutes, they are a good guide because they demonstrate to us the relative difference between the highest survival priorities. So where do “food, clothing and shelter” fit into this? Food is on the list, so we know where that comes in; but what about clothing and shelter? Those are both part of the same survival priority; they are used to help us maintain our body temperature, specifically to help us keep from losing core body heat.
<span style=”font-size: 11px;”> [1] Many people leave the need for oxygen out of this rule, but it is more properly stated to include it, as it is our highest survival priority.</span>
Oxygen
We get oxygen from the air that we breathe. Putting it in a simplistic way, every time we inhale, the lungs remove oxygen from the air we’ve breathed in and replace it with carbon dioxide, which we exhale. The human body then uses oxygen for a variety of things. Of those, the brain is the largest user of oxygen. While the brain stores a supply of oxygen, that’s only enough to last for a few minutes. After that irreversible brain damage occurs.
Besides being underwater, we might find ourselves in situations where we are lacking oxygen (if we are caught in a fire or a gas leak). In both cases, other gases are being inhaled into our system, keeping our bloodstream from absorbing the oxygen we need. Other kinds of disasters like the aforementioned pandemic flu or chemical attack could lead to the air we breathe being compromised or unsafe. In these cases, while the air is still technically breathable, based on the survival priorities, our first goal should be to get our hands on a chemical/gas mask that can filter the air and make it safe to breathe.
Body Temperature
The human body is designed to operate within only a very small temperature range. If the core body temperature rises or falls only a few degrees, it’s enough to cause the person difficulty in thinking clearly and control their muscle movements. A few degrees more and it can kill.
The loss of core body temperature is more common and usually more serious than overheating, although both can kill you. Nevertheless, it is easier to lose body heat than gain it. Gaining body heat normally only happens through infections and disease. Yes, it is possible to gain body heat when doing physical activities in a hot ambient temperature, but the body has ways of shedding that heat, keeping it from becoming dangerous. Excess heat generally only occurs in very extreme situations. Excess body heat is called “hyperthermia.”
On the other hand, if the body is losing core heat, it can only do so much to produce more. It is not hard to reach a point where heat is leaving the body faster than it can produce that heat. That’s called “hypothermia.” It’s the biggest killer in the wild. Hypothermia most often occurs when someone gets wet and leaves their wet clothing on, rather than drying off and replacing it. Water is more conductive than air (25 times more conductive) – that’s why we feel extra cold in water even if it’s the same temperature as the air around us (and also why hot water feels ‘hotter’ than hot air of the same temperature). That means that if you’re in wet clothing, you’re losing core body heat about 25 times faster than in dry clothing – which in turn means that it doesn’t need to be very cold temperature wise for you to get hypothermia if you’re wet. This is extremely important to remember – hypothermia can occur very quickly even in ‘not-so-cold’ temperatures if you’re in wet clothing.
Both clothing and shelter are used to help maintain body heat. Clothing acts as an insulator to keep your body’s heat in, close to your body, while shelter acts as a barrier to keep the weather from affecting your body. Specifically, survival shelter provides protection from rain and wind (both of which lead to faster decreases in core body temperature). Modern shelters, like your home, are also insulated to help hold in the heat that the heating system produces, allowing for warmer-than-outside temperatures to be maintained.
Clean Water
When we refer to clean water in a survival sense, we’re referring to it being biologically clean. That means that there are no microscopic pathogens in the water (bacteria, viruses and protozoa). While there can be other dangerous things in the water (such as minerals and chemicals) these are the ones we are most likely to encounter, and they bring sickness along with them.

Because we can’t see these microscopic pathogens, it is necessary to assume all water is suspect in any survival situation. Before drinking it, it must be filtered or purified to remove the pathogens. While filtering is the most common method of making water safe to drink in a survival situation, not all water filters work that well. You want at least a 0.2 micron filter.
Water can also be purified by both chemical means and through heat. These will kill the pathogens, even though it doesn’t remove them, preventing them from having any effect on our bodies. That means that on top of water filters, water purification tablets and boiling water are also valid ways of making ‘wild’ water safer to drink.
Food
Food is the lowest priority in the Rule of 3s; mostly because we can live off of stored energy in our bodies. While different experts will tell you different figures about how long a person can live without food (up as high as 100 days), the low end of that range is 30 days. Even if we can survive longer than that, our bodies will function much less efficiently after those first 30 days due to the lack of proper nutrition.
For short-term survival (less than 30 days), we are only concerned with the three macronutrients:
- Carbohydrates – which break down in the body to form simple sugars, the energy source for our bodies
- Fats – which break down slower into simple sugars, giving us long-term energy
- Proteins – which are the basic building blocks for new cells. If we don’t eat proteins, our bodies will cannibalize themselves in order to make those new cells
As long as we are receiving those, our bodies can continue to function. But once we use up the stored micronutrients in our bodies, it begins to affect our health. As a general rule of thumb, once you go past 30 days, you need to add back in the micronutrients (which are mostly found in fruits and vegetables) in order to maintain your body’s health. Micronutrients are things like Vitamins, potassium, calcium and so forth.
Are Those All Our Priorities?
While the items covered by the Rule of 3s are our highest survival priorities, they are not the only things we need to concern ourselves with. There are four other important areas we need to be aware of. These aren’t considered as important, because they are not needed in all situations. Even so, chances are that you will need them; and if you need them, you’ll really need them. These are:
Fire
Fire is probably mankind’s most important discovery. I say “discovery,” rather than “invention,” because early man’s introduction to fire was probably through something like a fire caused by a lightning strike.
We use fire for a number of very important things, including providing us with heat, light and for cooking our food. We can even use it to purify water. As a survival tool, fire is indispensible; so much so, that gathering wood and starting a fire is one of the first two things that any of us should do when establishing camp. The other is erecting a shelter.
First-aid & Personal Hygiene
If you become wounded or injured, then proper first-aid can suddenly become your highest survival priority. Unless the flow of blood can be stopped and infection can be avoided, the injured person can die. How fast they die will depend on how fast they bleed out or how fast the infection spreads. It’s ideal if at least one member of your survival team is trained and equipped to render first-aid for major wounds or injuries. Barring that, every survivalist and prepper should have some basic first aid knowledge, with a particular focus on severe injuries. Human bodies heal reasonably well from illnesses and injuries if given time. Therefore, when thinking about first aid, your focus should be on situations where time is of the essence – e.g severe/deadly injuries, heavy bleeding, and things of that nature.
Personal hygiene is closely related to first-aid, in that the lack of proper hygiene provides a breeding ground for bacteria, protozoa and viruses; which can result in sickness or disease. Ideally you can find a way to cleanse and stay hygienic even when out in the wild (or in a post-disaster urban situation).
Self-Defense
This survival priority only becomes necessary if you are attacked by two-legged or four-legged predators. Yet it is something that cannot be ignored. Two-legged predators (e.g other people) tend to come out of the woodwork in the wake of any disaster. Some do so because that’s what they are. Others might become predators for no other reason than that they are desperate and trying to find the things they need for survival.
Either group isn’t going to be concerned about your life; they’re concerned about their own. If killing you is the price they have to pay in order to secure additional resources, then they’ll be more than willing to do so. You have to be trained and equipped to defend yourself should that happen.
In short, self defense is important because when push comes to shove, it doesn’t matter if it’s a person or an animal – if you have food, or something else that could help them survive, they might very well come after you.
Keep in mind that self defense doesn’t just mean hand-to-hand combat – having access to weapons and other deterrents also count as a form of self defense.
Communications
While not actually a survival skill, the ability to communicate with others can save your life. If you become lost or injured in the wilderness, you probably won’t be rescuing yourself. In that case, you’ll need to find a place to make camp and wait for rescuers to come to you.
Whenever you head out into the wilderness, or travel anywhere for that matter, you should let someone know the following: Where you are going, the route you are taking and when you expect to be back. That way, if you don’t return, they can raise the alarm and send rescuers looking for you.
You can make the rescuers job a whole lot easier by being able to call out to them while they are searching. If you have signal for your cell phone, you can use that. However, chances are you won’t have signal. In that case, you can call out to them with a whistle (3 blasts is the international distress sign) or using a mirror to reflect light.

Putting it Into Practice
Once we understand what our priorities are, it is easy to know where we need to concentrate our efforts if and when we find ourselves in a survival situation. We must always start at the top of the list, making sure we have air to breathe and that we can maintain our body heat. From there, we move on to finding water and purifying it. Finally, we work on providing ourselves with food.
As a practical matter, in a wilderness survival situation, you want to stop traveling at least two hours before sundown. That time should then be used to find firewood, start a fire and build some sort of shelter. The night will be colder and you have to be ready before it comes. It doesn’t take very cold temperatures for you to be at risk of hypothermia, and this is particularly true if it starts raining. That’s why shelter and fire are so essential.
Finding water and food can be left to the next day. If you’re in an urban or wilderness survival situation you should be looking for food and water every day so that you can secure it for the night. You should never be in a situation where you’re forced to locate food and water at night.
Every year, a number of people die of hypothermia (even in the summertime) because they don’t follow that one simple rule. They might be up in the mountains fishing and fall into the water an hour before sundown. Rather than starting a fire and building a shelter to get them through the night, they decide to walk back to their car. But when night falls and the temperature starts dropping, their body starts to lose heat faster than it can generate it. Before long, they reach the point where they can’t think clearly enough to recognize their own car – let alone get to it.
That’s why as survivalists it’s important to fully grasp and understand the Rule of 3s and apply it. Don’t be a statistic. Getting caught in rain in the wild or falling into a river shouldn’t be a death sentence, but for many people it can be – because they didn’t recognize that they suddenly went from a relaxing day of fishing into a survival situation and they don’t take the appropriate action.
Allow the survival rule of three to inform all your decisions when you’re out in the wilderness (or in a post-disaster urban situation) and you’ll stand a much better chance of survival.

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Carry a knife of some sort as in your EDC, a good quality locking blade knife is an excellent option. I also have a 9MM diameter by 4 “ long with a key ring set up ferro rod . These items are on my person and the other items can be in your daypack or messenger bag. Practice with the gear you have and deploying them will come second nature.