How long can you survive in a rainforest?

A tropical rainforest removes the two fastest killers: there is abundant water, and night temperatures rarely threaten hypothermia. What it substitutes is a slower set of problems. Constant humidity means wounds do not dry and minor cuts become infected within days, footwear rots, and skin breaks down. Navigation is genuinely hard because the canopy hides the sun and horizon, and following a stream downhill — the standard advice — can take days through terrain that is exhausting to cross. Edible food exists but is not obvious, and misidentification is a real risk. Juliane Koepcke's survival after a 1971 air disaster in the Peruvian Amazon took eleven days of following water downstream, and infected wounds were her most dangerous problem, not hunger.

What changes the figure

• Following water downstream eventually reaches people
• Keeping wounds clean and covered matters more than food
• Staying put is usually better if anyone knows roughly where you are

Compiled from documented jungle survival accounts; conditions vary hugely between forest types and seasons.

Physiology, not instruction. Every figure here is a population range under particular conditions, and individual variation is large — temperature, exertion, fitness and health move all of them substantially. Nothing on this page is medical advice.

Places

• How long could you survive in deep space? About fifteen seconds of consciousness, and roughly ninety seconds before the damage becomes irreversible.
• Could you survive on Mars? Unprotected, under two minutes. In a pressurised habitat, indefinitely — the limits become supply and radiation.
• How long can you survive in the death zone on Everest? Hours to a couple of days. Above about 8,000 metres the body deteriorates no matter what you do.
• How long can you survive adrift in the open ocean? In warm water with a raft, three to five days without drinking water — but immersion in cold water is measured in hours.
• How long could you survive on the Moon? About fifteen seconds of consciousness without a suit. With one, the record stay is 75 hours.
• How long could you survive in the Mariana Trench? Unprotected, no measurable time at all — the pressure is over a thousand times atmospheric. In a submersible, as long as the life support lasts.
• How long can you survive in Antarctica? Minutes to an hour unprotected in a winter storm — or indefinitely, since around a thousand people overwinter there every year.
• How long can you survive in the Sahara Desert? Around a day without water in summer daytime heat, and several days if you can stay in shade and move only at night.
• How long could you survive on Venus? Seconds. The surface is 465 °C at ninety-two times Earth's atmospheric pressure — the hardest place in the solar system to land on.
• Could you survive on Jupiter? There is no surface to survive on — you would fall inward until pressure and heat ended it, within minutes.
• How close to the Sun could you survive? Nothing solid survives contact — but a shielded spacecraft has flown within about 6 million kilometres of the surface.
• How long could you survive on a desert island? Fresh water decides it. With a spring or reliable rain, years; without, about three days.
• How long can you survive on the International Space Station? Indefinitely while it is resupplied — it has been continuously crewed since November 2000.
• How long can you survive in the Arctic? Hours unprotected in winter — but roughly four million people live above the Arctic Circle permanently.