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Namib Naukluft National Park, Namibia. (Photo by Michael Poliza)
Once again I have been thinking about the Namib Desert–the world’s oldest desert–which calls to me for reasons I cannot fully explain. I wrote about some of the Namib’s strange animals and plants…but one thing I did not mention was its ergs. This is because I did not know what an erg is, but today I looked it up and the concept is simultaneously horrifying and beautiful. An erg is a sea of wind-blown sand. This geographic feature is not unique to the Namib Desert—or indeed to planet Earth—but they do tend to be found only in vast & mighty deserts. Such a landscape is characterized by vast dunes—mountain-like sand hills composed of immense numbers of individual sand grains.
A sand dune in the Rub al Kali Desert
Geographers have seemingly fixed certain parameters on how large a sandbed must be to count as an erg—but I will let you look these up on your own—I think the word “sea” covers the scope of ergs. We are not talking about a child’s sandbox here.
Issaouane Erg, Algeria (photo from the International Space Station)
The word erg derives from an Arabic word “arq” which means dune landscape. The Rub al Kali Desert “the empty quarter” of Saudi Arabia is a vast erg—the world’s largest. There are a multitude of ergs throughout the Sahara (as seen on the map below) and they can also be found in central Asia, the middle of Australia, and the Atacama Desert (which I also really need to write about). Ergs are less common in North America than in Asia and Africa, but there a few notable examples mostly in the Sonoran Desert, but also including the unimaginatively named “Great Sand Dunes” in Colorado.
The geology of ergs is quite fascinating as the dominant agent of erosion and change is wind rather than water. When wind activity shapes the surface of the Earth (or another planet), geologists describe the varying sorts of erosion, deposition, and weathering as “Aeolian processes” in homage to the ancient Greek god of the winds who crops up in the Odyssey and the Aeneid. Ergs do not just feature great dunes but also strange sand sculpted rocks and dry river beds.
White Sands, New Mexico
As noted, ergs are not a phenomena exclusive to Earth, but can be found on other planetary bodies too (if they have silica and atmospheres). Ergs have been discovered on Mars where vast erg fields ring the polar caps. The Martian winds blow the ergs into bizarre patterns and shapes (usually I would say “otherworldly”, but that seems too pedestrian a word here). Venus also has ergs (discovered by the Magellan probe) and Cassini’s radar spotted huge parallel ergs on Saturn’s great moon Titan. Indeed ergs may be the dominant surface feature of Titan.
Martian Polar Dunes (photographed by the Mars Odyssey Spacecraft)
I have never been to an erg. There are none in Brooklyn (yet). However I would like to see one…although I admit to a certain amount of trepidation. They do not seem like places for life, and indeed they are among the most lifeless places on all of Earth. Ergs are beautiful but also terrible and dangerous. At least they should stay free of suburban sprawl for long enough for me to visit one (and it will probably be a very long time indeed before we cover the ergs of Titan with strip malls).
Erg Chebbi in Morocco (Bjørn Christian Tørrissen)
The Gobi Desert
When I think of China, I tend to imagine coastal China or the Yangtze River valley—which is to say areas of tremendous human population density where neighbor lives smashed up against neighbor and black smokestacks belch poison smoke onto the churning masses. Yet China is truly vast and parts of the nation are among the least densely populated places on Earth. The great northwest deserts of China are a land of shifting sands, xeric scrubland, and nothingness. Yet the dry wasteland is home to one of the world’s rarest and fanciest leaping rodents.
The Long-eared Jerboa, Euchoreutes naso, is an insect-eating, long-jumping, mouse-like creature which lives in the deserts of China and Mongolia. The animal’s habits are largely unknown–since it is a master of stealth and also since it lives in such an unforgiving and desolate regions where biologists are infrequent guests. The long-eared jerboa is sufficiently distinct that it is classified in its own genus and its own subfamily. It is (self-evidently) notable for its long ears which it uses to hunt insects in the desert nights and to avoid predators.
The Long-eared Jerboa, (Euchoreutes naso)
The animal is lightweight with a mass of only 24 g (0.85 oz) to 38 g (1.3 oz) and its body is small, measuring from 70 mm (2.8 in) to 90 mm (3.5 in)—although its tail is just as long as its body so the whole creature measures up to 180 mm long (7 inches) if you count the tail. Like other jerboas, this species probably excavate burrows where they rest during the day. Because they are so enigmatic and poorly understood (and also so endearing), the long-eared jerboas are a kind of symbol of truly wild creatures and the little rodent was identified as one of the top-10 “focal species” in 2007 by the Evolutionarily Distinct and Globally Endangered (EDGE) project.
The Skeleton Coast of Namibia (photo from grandpoohbah.net)
Try to imagine the Namib Desert, where a stormy foggy shoreline gives way quickly to endless bone-dry dunes of shifting golden sand. It is one of the starkest contrasts in the world’s geography: the fury of the cold waves is juxtaposed with the opposing starkness of the sun-pounded dunes.
The coastline where the Namib Desert runs up against the Atlantic is known as the skeleton coast both because it is a place where whalers and sealers once discarded the stripped carcasses of the marine mammals they killed in droves and because it is one of the world’s most treacherous coastlines. More than a thousand major modern wrecks dot the coast (where they mingle with countless older shipwrecks). Portuguese sailors trying to get around the horn of Africa to reach the riches of Asia called the area “the gates of hell.” A human powered craft can make its way through the pounding surf to the desolate coastline but it then becomes impossible to re-launch. Sailors shipwrecked on the Namib coast thus faced the daunting prospect of walking through a vast expanse of waterless desert. Before the modern era, most ship-wrecked souls did not escape and their skeletons soon became part of the landscape.
The shipwreck of the Eduard Bohlen (photo by Michael Poliza)
The desert is ancient. For more than 55 million years it has existed as a wasteland with almost no surface water. Since the end of the age of dinosaurs, the warm tropical air of the Hadley cell has intersected a cold oceanic current welling northward from Antarctica. But the region was arid long before that. West Gondwanaland shifted to its present position along the Tropic of Capricorn nearly 130 million years ago and has remained there since—a wallflower in the great dance of continents.
The Namib Desert photographed from The Space Shuttle Columbia
Namibia was a German colony during the colonial era. Unsurprisingly, the Germans made their Namibian colony the sight of the twentieth century’s first genocide when they tried to extinguish the unruly Herero and Nama peoples in 1904. The nation was seized by South Africa after the end of World War I but after many decades of gradual power shifting Namibia gained complete independence in 1990.
The Republic of Namibia is the second sparsest nation on earth with only 2.1 million people spread across a landscape roughly the size of Germany, Poland, the Czech republic, Belgium, Denmark, and the Netherlands combined (not that those nations should ever be combined!). It is one of the few stable multi-party democracies in Africa (maybe I should say the world). Namibia makes most of its money from mining uranium, gemstones, lead, tungsten, gold, tin, fluorspar, manganese, marble, copper and zinc. Natural gas can be found just off the coast (though it may prove challenging to drill there).
The Navachab Open Pit Gold Mine, Erongo Region, Namibia
Why am I writing about this beautiful harsh anomaly of a nation? The unique and isolated geography of Namibia have made it a unique ecosystem of creatures capable of surviving the harsh desert environment (to say nothing of the creatures which team in the rich coastal waters). Desert dwelling creatures have had a long time to adapt to the hostile conditions of the world’s oldest desert. One of the most unique of all placental mammals is found in Namibia. I’ll address this bizarre fossorial hunter in my next post.
Hint: It's not the mighty African Elephant (one of my favorite creatures), but strangely enough african elephants do live in Namibia.
ferrebeekeeper 