Surviving under harsh conditions is one thing. Growing for 1,500 years, building dunes and producing melons is quite another. Meet two plants that have perfected life in the desert.
A Welwitschia mirabilis plantImage: Rainer Dückerhoff
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Even marketers are leveraging the power of the fascinating welwitschia plant.
"It outlasts and it survives … it blooms where others falter and shows growth over time," reads a billboard at Windhoek airport in Namibia, promoting an asset managing company.
The desert plant Welwitschia mirabilis is indeed an extraordinary plant, mastering life in the hot, dry desert where other plants can't survive.
It only grows in the Namib desert within Namibia and Southern Angola. It's also the national plant of Namibia.
Even the Namibian national rugby union team is named after it.
Its full Latin name shows that the researchers who discovered the plant were amazed by it as well: "Mirabilis" is the Latin word for "marvelous."
Nowadays, it's referred to as a "living fossil."
Up to 1,500 years old
At first sight welwitschia plants might not appear quite impressive, particularly when they're still small.
They grow close to the ground and, apart from the pale green leaves, they look almost… dead.
This giant, 1,500-year-old welwitschia is a tourist attractionImage: Rainer Dückerhoff
The older, larger specimens, particularly the giant welwitschia, are impressive to the point of becoming a tourist attraction.
There's one growing 50 kilometers (31 miles) east of the Namibian town of Swakopmund on the Atlantic coast - and it's as tall as a human being, estimated at roughly 1,500 years old.
A fence keeps people - and their feet - from trampling its sensitive root system growing close to the ground.
"Fog kept the plant going for so many years," says Titus Shuuya, a welwitschia researcher at the Gobabeb training and research station in the Namib Desert. "Welwitschia's fine root hairs can capture the moisture."
A young welwitshcia plant - see the two leaves?Image: Rainer Dückerhoff
Welwitschia has just two leaves, which continue growing for as long as the plant lives. Titus Shuuya discovered that they grow an average 0.37 mm per day.
Monja Gerber, a biologist and desert plant specialist at Gobabeb, says the growth doesn't happen uniformly, though.
"When environmental conditions aren't favorable, growth decreases, so that it doesn't use a lot of energy," she says.
The plant's patience - just sitting and waiting for better conditions - makes it so persevering and lasting.
"These plants can teach us a lesson," Shuuya says.
Making its own shade
Even 1,500-year-old welwitschia plants have just two leaves. They're not easy to see, though, as the leaves grow very long and split multiple times at their ends.
Those long leaves wrap around the bottom portion of the plant.
"They give shade to the root hairs, and thus protect the plant from losing water," Shuuya explains.
Welwitschia plants have a gender: Male plant on the left, female on the right
Welwitschia can also adjust the color of its leaves. When it's very hot, the leaves produce more red pigments, which protect the plant from the sun's radiation. When temperatures drop and water is more readily available, the leaves form more chlorophyll, the green pigment, to conduct photosynthesis.
"These [color] changes are visible," says Monja Gerber, adding that the photosynthesis rate is also generally higher toward the bottom of the leaves, which are turned away from the sun.
Building its own sand dunes
A sand dune, constructed by the nara plant atop itImage: DW/B. Osterath
Not as famous as welwitschia, but biologically impressive nevertheless, is the nara plant (Acanthosicyos horridus).
It is a leafless, spiky thicket that grows only in the Namib Desert. By forgoing leaves, it prevents water loss. Instead, it conducts its photosynthesis directly through its green stems and spines.
The plant also absorbs moisture from fog directly through its stems.
"The more time I spend with it, the more it reminds me of an intelligent plant," says Monja Gerber, who's doing her master's thesis on the nara. "It can actually manipulate its environment to better suit itself."
Nara plants provide shade for animalsImage: Picture alliance/Mary Evans Pictures
Nara plants grow on top of sand dunes in the middle of the desert. The special thing about that, though, is that the sand dunes weren't there previously. The plant constructed them.
This is how it works: Nara plants growing on the ground accumulate sand around them, blown in by the wind. The lower part of the plant, which is covered in sand, dies off and provides nutrients for the rest of the plant. New plant parts then grow on top of the old one. The nara plant gradually gains height as a result, accumulating even more sand.
In this manner, the plants grow up to 3 meters high.
'A melon in the desert is not normal'
What really makes the nara so special, though, is its fruit.
Female nara plants produce tasty orange-yellow colored melons, which grow as big as ostrich eggs.
As Monja Gerber puts it: "A melon in the desert is not normal."
The fruits are not only a water-rich food source for animals around, but also for humans.
The Topnaar people - an ethnic group native to Namibia that lives in the Namib Desert - harvest those melons seasonally.
They eat the flesh but also sell the seeds, which can be used to produce cosmetic products due to their high omega oil content.
"The Topnaar people depend on the nara plant as a source of income to sustain their livelihood," Monja says.
She's part of a project team that's trying to cultivate the nara on a larger scale to help the struggling Topnaar communities.
Nara cultivation isn't possible - yet. As soon as you try to establish a germinated nara seedling, it just dies off. Nobody knows why, Monja says.
Maybe the plant just wants to decide on its own where it wants to grow.
In any case, desert plants like the welwitschia and nara are highly adjusted to their environment.
They only grow in certain parts of the Namib desert - and that's it.
Survive and thrive in the Namib desert
Scorching hot by day, freezing at night, scarce water and food supplies - the Namib desert in southern Africa is a hard place to live. But these animals have found ways to cope with the hostile conditions.
Image: R. Dückerhoff
Take what you can get
Ostriches do not mind the hot and barren African desert. The flightless birds can raise their body temperatures to stop them sweating and reducing water loss. They get all the water they need from the plants they eat. They also swallow small stones, which grind food in their stomach. Their intestines can handle things that other animals can't digest.
Image: picture-alliance/Arco Images/C. Hütter
Keeping cool in the heat
Gemsboks also raise their body temperature on hot days - up to 45 centigrade (113 Fahrenheit). A network of small blood vessels in their noses cools the air they breathe, and that keeps their brains cool too. The gemsbok's underpart is white, reflecting the heat radiating from the ground. They get fluids from water-rich foods such as roots, tubers and the tsamma melon, which grows in the desert.
Image: picture-alliance/Photoshot
Pick a color
Too hot? No problem for the Namaqua chameleon. It simply changes its color to become lighter and reflect more sunlight during the heat of the day. In the cooler mornings, though, they are black. Their tail is quite short compared to other chameleons. They don't do a lot of climbing in the desert, but they do climb on rocks and small bushes to get away from the hot sand in mid day.
Image: R. Dückerhoff
It's cooler higher up
The Namib Desert dune ant's legs are about five millimeters long. They lift the ant to a height where temperatures are up to ten centigrade (50 Fahrenheit) cooler than directly on the sand surface. It gets its fluids from honeydew, excreted by plant-sucking scale insects. Even though the ants look conspicuous on bare sand, predators shrink away from eating them: formic acid spoils the meal.
Image: DW/B. Osterath
Going underground
The Namib sand gecko (Pachydactylus rangei) avoids the heat of the day by digging burrows and only coming out at night. Its large eyes help it to find prey in the dark. Its webbed feet are perfect for burrowing and walking on sand. The gecko's skin is translucent so that some of the internal organs can be seen. Its color allows very good camouflage in the sand of the desert.
Image: R. Dückerhoff
Night dancer
The Dancing White Lady Spider (Leucorchestris arenicola) also likes to avoid the sunlight. It constructs a 0.5 meter deep burrow out of sand and silk where it hides from the heat. As the spider only comes out at night, it doesn't need sun protection, hence its white color. When mating, the males tap their foremost legs on the sand, giving the species its "dancing" name.
Image: R. Dückerhoff
Easy does it
"Go slow" is the motto of the Namib Dune Scorpion (Opistophthalmus flavescens) when it comes to metabolizing. The animal doesn't need much energy and can wait for months until the next meal arrives. The oxygen transport system in the scorpion's blood is different from ours and isn't hampered at high temperatures - perfect for life in the desert! It digs three meter deep burrows to live in.
Image: R. Dückerhoff
A nose like a shovel
The sand in the Namib dunes is so fine that some animals swim through it – as if it were water. They don't even have to dig. It's true for this shovel-snouted lizard. The shape of its head allows it to move through sand without resistance. It's good for escaping from predators where cover is sparse. Its nostrils face backwards and have a cartilaginous flap to prevent sand from entering.
Image: R. Dückerhoff
A life in the sand
The FitzSimons' Burrowing Skink can also swim through sand. It spends its whole life in the sand of dunes, where is searches for food, such as small insects. It detects its prey by feeling for vibrations created by the insects when they move.
Image: R. Dückerhoff
Hide and eat
This snake, the venomous sidewinding adder, has found the perfect way to catch prey in the Namib desert. It burrows itself in the sand, leaving only its head sticking out – but it looks just like the sand. It moves with characteristic side-winding movements through the fluid sand, hence its name. Sidewinding allows the snake to move over hot sand without overheating.
Sociable weaver birds meet most of their water needs through their diet, which consists mainly of insects. They build huge nest structures, housing hundreds of birds of several generations at a time. The chambers inside the nests provide shade and are cooler than the outside, whereas the central chamber retains heat and is the ideal place for night time roosting.
Image: R. Dückerhoff
In all shape and sizes
Beetles are central to the food supply in the Namib desert. They feed on detritus, dead organic matter from plants which is blown into the desert by wind. During early mornings, they collect water droplets from fog. Other animals feed on the beetles to get their water. About 200 species of beetles roam the Namib desert. Most hide in the sand.
Image: DW/B. Osterath
Harvesting water
The fog basking beetle has a peculiar way of collecting drinking water in the Namib desert. In the morning, it runs up the dunes and does a headstand. Fog condenses on its back, and droplets run down towards its mouth. They can drink up to 40 percent of their body mass on one morning. The species is also known as the head-stander beetle.
Image: picture-alliance/Wildlife/M. Harvey
Playing dead
Get eaten by other animals? No way. This weevil has other plans. When it is threatened, it drops on its back and plays dead, hoping its predators have no appetite for dead, dried-out beetles.
Image: DW/B. Osterath
Life under rocks
There is life everywhere in the Namib desert, even under rocks! Cyanobacteria grow there. Enough sunlight penetrates this white rock for the bacteria to perform photosynthesis. In the blazing sun, though, they die.
