In 1981, Yossi Ghinsberg, together with his three friends, journeyed to the Tuichi River in the Amazon. Caught in the immensity of the forest, they got lost and worse, were ill-equipped to handle a survival situation. They decided to break off in pairs, with Yossi partnering with Kevin. The two rode a raft downriver, which hit a rock, and decided to split up. Nothing was ever heard of the other couple again. For the next 19 days, Yossi wandered aimlessly in the wilderness. Kevin was rescued by local men and a search was conducted to look for Yossi and his companions. Luckily, Yossi was found and needless to say, was transformed by the whole ordeal.

Yossi’s secret in surviving the wild was a combination of clear thinking and yielding to the situation. “When adversity strikes, when everything suddenly changes the best possible strategy is not resisting but rather adapting,” says Yossi, who is now a motivational speaker. “Adaptation is the very essence of survival and survival is something we do not need to learn.”

Wilderness medicine and survival expert Greg Davenport agrees. Rather than spending energy figuring your escape route, you should pause on your tracks and “recognize the situation for what it is.” Your best survival tool is your brain, which will guide you to use available resources that will make the difference on whether you will come out of the wilderness alive.

Water

There is no doubt that the single most important thing that will determine the chances of survival in the wild is water. “Without water, you'll perish in three to four days; without food, you can live for threeor more weeks,” says Greg. So if you find yourself in a place without water supply, you should not waste time and start looking for a pond, a brook or a river.

Lush vegetations and animals indicate that a water source is nearby. “A swarm of insects can indicate presence of water close by,” says Debopriya Bose, a science teacher writing for Buzzle.com. “Also look up to the sky. If you see birds circling over a particular area, a water hole may be present.” Fresh water also gets collected on leaves and in between stones but should be boiled to get rid of parasites.

Fire

After water, fire is the next vital supply that should be readily addressed. In the wild, it serves a variety of uses: boil water, cook food, offer warmth during the nights, keep the wildlife from getting near you, and lift your spirits. It will be good to have a match or a lighter but it will run out over time and all you will have to make a fire are the materials around you.

In order to create fire, you will need, tinder (crushed fibers from dead plants, wood shavings and dry grasses), kindling (dry twigs, cones and needles), and fuel (wood of fallen trees, large branches). A spark can be started by any convex lens (flashlight and camera lens or magnifying glass) by directing concentrated light on the tinder. In the absence of any source of spark, one can do the “Bow and Drill,” a method where friction that leads to heat is created between a soft wood and hard wood by the repetitive twisting of string.

Food

Sustenance is the key in order for you to have strength and think clearly of your next move. Debopriya advises to “stick to known plant specimens like nuts, berries, and fruits while looking for food in the wild.” She adds that if you see animals feeding on a particularly plant, chances are it also edible. Rabbits, squirrels and other mammals can provide a good source of protein but it takes a certain level of skill to hunt them. Insects, on the other hand, are plenty and you can feed on ants, slugs (but should be boiled first), larvae, grasshoppers, maggots and earthworms. Not all bugs are edible and be sure to avoid those associated with disease (ticks, flies, mosquitoes) and carry venom (centipedes, scorpions, and spiders). Greg maintains that bugs with “fine hairs, bright colors, or eight or more legs” should not be eaten.

Plants are of course the most available source of nutrition. One way you can determine whether a plant is safe to eat is through a test established by the US Army. After breaking the plant into its basic parts (roots, stem, leaves), smell it for strong or acidic odors, which indicate that they are not edible. Rub a sample of the plant on either the inside of your elbow or your wrist for 15 minutes and wait for any reaction. If no redness or itchiness occurs, repeat the process, this time on your lips and then on your tongue. You can chew and swallow a bit of the plant and if your stomach doesn’t react, then you can increase your consumption little by little.

Shelter

You should be able to create your own shelter as a protection from the elements and the wildlife using the available materials around you. “Create a stable framework that will support the weight of the walls; a roof with enough pitch to repel rain and snow; and insulation in the roof, walls and floor to keep you warm,” Greg advises.

Nature itself may already have an available lodging for you. “Caves make for a fantastic shelter - you just have to be sure you’re not sharing with any other occupants, like bears,” says Johnny Dunn. “Natural hollows can be very easy to find and all you need to do is gather a few strong branches, sticks, and grass for a roof…You could also take residence in a fallen tree trunk. Just scoop out a hollow, cover it with some boughs for a roof, and you have a place to sleep.”

Signaling

Alone and needing rescue, you have to have the materials on hand to communicate your presence to the outside world. Signaling tells rescuers that you are still alive and desperate for help. Manager of Canada West Mountain School, Brian Jones states: “Make messages, get some signs out on the snow, so if searchers are looking, they will see your tracks. Be creative.” A signal, says Greg, “can be as simple as blowing a whistle or scanning the horizon with the flash from a mirror.” You can also beat metal objects to announce your presence or create a sign that will contrast to the ground and be visible from hundreds of meters up. Exercise caution when you transmit your signals as you may attract people who might take advantage of your situation.

If in case you are in a place where rescuers will not be able to locate you such as a dense forest, Man vs. Wild host Bear Grylls suggests to find a river. Pay close attention to the sound of rushing water. For centuries, communities have thrived beside this body of water and walking downstream might bring you to a village. The river is also a good source of your two basic needs: drinkable water and food in the form of fish.

Positive attitude

Another thing to consider is one’s emotional and mental attitude. Losing hope will easily cripple one’s resolve to go on and seek for help. “Put the negative thoughts into perspective, and don't dwell on them,” Greg suggests. Little successes such as building a fire or catching a squirrel for food should be viewed as positive signs. Combined with adequate resources, presence of mind, and a sharp survival instinct, hope, just like in the case of Yossi Ghinsberg, can save someone in the most terrible of situations.