The Namib desert in southern Africa is a hostile place: scorching hot by day, freezing at night, and there is little to eat in the barren landscape. But an amazing array of species has evolved here. Here's why.
Image: picture-alliance/Wildlife/M. Harvey
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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.
Image: R. Dückerhoff
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We all know the golden rule: where there is water there is life.
But water can take many forms - it doesn't have to appear as rainfall or flowing rivers. And in the Namib desert water comes as fog.
It is all due to the Benguela current, a cold ocean current which brings icy waters from the depths of the Atlantic Ocean to South Africa's and Namibia's western coasts.
"The Benguela current interacts with warm moisture above the sea surface," says Roland Mushi, a research technician at Gobabeb Training and Research Centre in Namibia, in the middle of the Namib desert.
"The moisture is cooled down to form dew and then fog," continues Mushi.
Prevailing south western winds push the fog into the desert.
Gobabeb - a desert research center in the middle of the NamibImage: DW/B. Osterath
There aren't many foggy deserts like the Namib, but the Atacama desert in Chile is one other example.
Three hundred days of fog
Swakopmund on Namibia's Atlantic coast is a beautiful city, with its German colonial architecture, but the fog sometimes drives the residents crazy.
The city lies in a hotspot where the fog forms. So Swakopmund residents experience about 300 days of fog each year.
The fog forms in the early morning and stays for several hours, until about 10 am when it gets warm enough for the fog to clear.
While the people in Swakopmund complain about the fog, life in the desert desperately waits for it.
The fog over the dunes vanishes into thin air before noonImage: Rainer Dückerhoff
Evolution at its best
Desert plants like Welwitschia and Nara have evolved to take up water from the fog through very fine roots or through their stems, respectively. These plants only grow in the Namib.
Also, beetles and other insects in the desert collect moisture from the fog - and have found quite peculiar ways to do so.
The fog basking beetle, for example, harvests water by pushing his bum up into the air. Fog condenses on his behind and water droplets run towards its mouth for the animal to drink.
Another species of beetle, Lepidochora porti, digs trenches in which the fog collects and condenses. Geckos, snakes, birds and many other animals feed on the beetles.
Almost 300 animal species exist in the dune field of the Namib desert alone. Over half of those do not exist anywhere else in the world.
The area is listed as a natural World Heritage Site due to its beauty and biological value.
