A2 · Elementary
10 min
survival sciencehuman biologysearch and rescuemilitary
The Desert and the Human Body
El Desierto y el Cuerpo Humano
Two American soldiers go missing in the Moroccan desert during military exercises. Fletcher and Octavio explore the science of human survival in extreme heat, and what the body does when it runs out of water.
Dos soldados americanos desaparecen en el desierto de Marruecos durante unos ejercicios militares. Fletcher y Octavio exploran la ciencia de la supervivencia humana en condiciones extremas de calor.
6 essential A2-level terms from this episode, with translations and example sentences in Spanish.
| Spanish | English | Example |
|---|---|---|
| el desierto | the desert | El desierto tiene mucho calor. |
| tener sed | to be thirsty (literally: to have thirst) | Tengo mucha sed después de caminar. |
| el calor | the heat | Hace mucho calor en el desierto. |
| el cuerpo | the body | El cuerpo humano necesita agua todos los días. |
| peligroso | dangerous | Caminar sin agua en el desierto es muy peligroso. |
| buscar | to search, to look for | Los soldados buscan agua en el desierto. |
Two soldiers went for a hike.
That sentence sounds almost ordinary until you find out where the hike was.
Sí.
Yes.
Los soldados están en Marruecos.
The soldiers are in Morocco.
Cerca de Tan-Tan.
Near Tan-Tan.
The U.S.
Africa Command confirmed this week that two American soldiers went missing near Tan-Tan, Morocco, while hiking after participating in Exercise African Lion.
That's an annual military drill, big multinational operation.
But these two stepped away from it, went for a hike, and didn't come back.
Tan-Tan es una ciudad pequeña.
Tan-Tan is a small city.
El desierto está muy cerca.
The desert is very close.
And that's the piece that stopped me.
Because I've been near that part of Morocco, the Anti-Atlas foothills bleeding into pre-Saharan terrain, and the landscape shifts fast.
You think you're on a trail and then you're not on anything.
El desierto es peligroso.
The desert is dangerous.
Hace mucho calor allí.
It is very hot there.
Which is what I want to dig into today, because this is a science question as much as a news story.
What actually happens to the human body in extreme desert heat?
How long do you have?
What does the physiology look like?
Because the search-and-rescue clock in situations like this is brutally short.
El cuerpo humano necesita agua.
The human body needs water.
Siempre.
Always.
Always and urgently.
Here's where it gets interesting scientifically.
At rest in mild weather, we lose maybe two liters of water a day.
In the Saharan fringe in May, with temperatures pushing fifty degrees Celsius in the sun, that number can hit ten or twelve liters.
Through sweat, through breathing, through simple existence.
Doce litros es mucho.
Twelve liters is a lot.
El cuerpo trabaja mucho.
The body works hard.
It does.
And here's the sequence: the first sign of dehydration kicks in at about two percent body water loss.
You feel thirsty, your mouth dries out, your concentration starts to slip.
At five percent you're getting headaches, your muscles cramp, your decision-making deteriorates.
At ten percent, you're in serious danger.
Past fifteen, the organs begin to fail.
Y la persona no piensa bien.
And the person doesn't think clearly.
El cerebro tiene sed también.
The brain is thirsty too.
That's the part that makes desert survival particularly cruel.
The thing that could save you, making good decisions, finding shade, rationing water, navigating toward help, is exactly the thing that degrades first.
Your brain shuts down before your legs do.
Es muy peligroso.
It is very dangerous.
En el desierto, el sol es el enemigo.
In the desert, the sun is the enemy.
The sun and the ground.
Because here's something people don't intuitively grasp: in the Sahara, ground temperature and air temperature are not the same thing.
Air temperature might be forty-two degrees.
The sand surface can hit eighty degrees Celsius.
If you collapse, you're lying on something that will cook you.
Ochenta grados.
Eighty degrees.
En el suelo.
On the ground.
Eso es increíble.
That is incredible.
I know.
And the animals out there have spent millions of years adapting to exactly this.
The fennec fox with those enormous ears that radiate heat.
The desert beetle in the Namib that tilts its body into the fog to collect water droplets on its shell.
These organisms have solved problems that human engineering is still trying to copy.
Los animales del desierto son muy inteligentes.
Desert animals are very smart.
Tienen mucha agua en el cuerpo.
They have a lot of water in their body.
Some store it, some extract it from almost nothing.
The thorny devil lizard in Australia collects moisture from sand through channels in its scales that funnel water directly to its mouth.
Scientists have been studying that for years, trying to apply it to materials that could harvest atmospheric water in dry regions.
It's one of the more quietly exciting areas of biomimicry research.
Los humanos aprenden de los animales.
Humans learn from animals.
Eso es bueno.
That is good.
It really is.
But let's come back to these two soldiers and what happens when humans are suddenly in that environment without those adaptations.
The body does have some emergency responses.
Core temperature rises, blood gets redirected away from the skin to protect vital organs.
But those compensations have limits, and they reach those limits within hours, not days.
Pocas horas.
A few hours.
El cuerpo es fuerte, pero no invencible.
The body is strong, but not invincible.
The medical literature on desert survival is pretty stark.
Without water, in full sun at desert temperatures, a healthy adult can be in a life-threatening condition within six hours.
The old survival estimate, three days without water, is calculated for temperate conditions.
In the Sahara in summer, you revise that number down sharply.
Seis horas.
Six hours.
Es muy poco tiempo.
That is very little time.
Los soldados tienen entrenamiento especial.
The soldiers have special training.
They do, and that matters.
Military SERE training, Survival, Evasion, Resistance, Escape, teaches soldiers exactly these physiological realities: stay in shade from ten a.m.
to four p.m., move at night, conserve moisture, signal for extraction.
Whether they had that kit with them on a casual hike after exercises is a different question.
Una caminata sin agua es un error grande.
A hike without water is a big mistake.
A potentially fatal one.
And it's a mistake that's been made many times by experienced people.
There's a documented phenomenon called voluntary dehydration, where even trained individuals don't drink enough because the thirst mechanism lags behind actual need.
By the time you feel urgently thirsty, you're already clinically dehydrated.
El cuerpo miente a veces.
The body lies sometimes.
La sed llega tarde.
Thirst comes late.
Beautifully put.
And now on the rescue side, this is where modern technology is genuinely remarkable.
Search and rescue operations in desert terrain now use thermal imaging drones because a human body in a desert landscape is a heat signature that stands out clearly against cooling sand at night.
The search window, counterintuitively, is often after dark.
Los drones buscan calor.
Drones look for heat.
El cuerpo humano tiene calor.
The human body has heat.
Eso ayuda.
That helps.
It does.
Satellite imaging has also transformed this, the kind of high-resolution terrain analysis that can identify where someone might have sought shelter, a rocky outcrop, a dry riverbed with possible shade.
You're essentially doing probabilistic modeling of how a disoriented person in declining health would move.
That's a whole subfield of search-and-rescue science now.
La ciencia ayuda a encontrar personas.
Science helps find people.
Eso es importante.
That is important.
It's one of the more quietly hopeful corners of applied science.
And it has civilian applications too, for missing hikers in places like the Moroccan Atlas, for refugees crossing the Sahara.
The same thermal drone technology, the same algorithmic search patterns.
Though the resources deployed are obviously very different depending on who's lost.
Sí.
Yes.
Hay personas en el desierto sin ayuda.
There are people in the desert without help.
Muchas personas.
Many people.
Tens of thousands make that crossing every year, and the science that could find two American soldiers within hours of their disappearance is not deployed for them.
That's not a criticism of the military, they're supposed to protect their own, it's just a fact about how the same tools get distributed very differently across different human lives.
Es una diferencia difícil.
It is a hard difference.
Pero el desierto es el mismo para todos.
But the desert is the same for everyone.
The desert doesn't care who you are.
That's actually one of the things that makes extreme environment science so interesting to me.
The body's rules are democratic.
Elite athlete, veteran soldier, someone with nothing, the heat treats you identically.
It's a leveler in the most unforgiving way possible.
El desierto es muy honesto.
The desert is very honest.
No tiene favoritos.
It has no favorites.
No favorites at all.
And Exercise African Lion has been running since 2002, twenty-plus years of joint operations between American forces and Moroccan and other African militaries.
It's one of the larger exercises on the continent.
The idea that a routine hike in the aftermath of that exercise ends this way is a reminder that the controlled environment of a military exercise is still surrounded by a very uncontrolled natural one.
La naturaleza no sabe de ejercicios militares.
Nature doesn't know about military exercises.
La naturaleza hace lo que quiere.
Nature does what it wants.
That it does.
Tan-Tan is also interesting as a place, because it sits right at the edge of the Western Sahara territorial dispute, Moroccan-administered, historically contested.
And the landscape just south of there is some of the most geologically ancient terrain on Earth.
Rock formations older than the first complex life.
I keep coming back to how indifferent all of that is to any single human story.
Las rocas son muy viejas.
The rocks are very old.
Nosotros somos muy pequeños en el desierto.
We are very small in the desert.
Very small.
And that might be the thing I take from this story, that the science of survival is really the science of humility.
Understanding what the body can and can't do, what the environment will and won't forgive, and building systems around those honest limits.
Oye, tú dices que nosotros somos pequeños.
Hey, you say we are small.
Pero tú también tienes mucho frío a veces, no?
But you also feel very cold sometimes, right?
I walked right into that.
Alright, alright.
Although I noticed something you just said.
You said "tienes mucho frío" for feeling cold.
Not "eres frío." That's one of those things that catches English speakers completely off guard.
Sí.
Yes.
En español, usamos "tener" para sensaciones.
In Spanish, we use "tener" for sensations.
Tengo frío.
I am cold.
Tengo calor.
I am hot.
Tengo sed.
I am thirsty.
So literally "I have cold" and "I have heat" and "I have thirst." In English we say I am cold, I am hot, I am thirsty, as if the sensation is your identity.
In Spanish you possess it temporarily.
Which, given today's topic, feels almost philosophically correct.
You have thirst.
You don't become it.
Sí.
Yes.
"Tengo sed" es correcto.
"I have thirst" is correct.
"Estoy sediento" también es posible, pero es más formal.
"I am thirsty" is also possible, but it is more formal.
Good to know.
So if I'm lost in the desert near Tan-Tan, I should probably say "tengo mucha sed" and not "soy embarazado."
Sí, Fletcher.
Yes, Fletcher.
"Tengo mucha sed" es perfecto.
"I am very thirsty" is perfect.
Y muy útil en el desierto.
And very useful in the desert.
Mucho más útil que estar embarazado.
Much more useful than being pregnant.