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Namib Sand Snake (Psammophis namibensis) by Cowyeow from Flickr
This endearing little desert snake is Psammophis namibensis, the Namib sand snake. As you may have intuited based on the name, the snake is endemic to the Namib Desert where it lives in the vast sand seas which stretch from the Atlantic coast deep into the African continent. The snake is little—the largest males are slightly more than a meter (three feet) in length and most are even smaller than that. It is whipcord thin with delicate dust-colored stripes running horizontally along the top of its body.
Juvenile Namibian Sand Snake (Psammophis namibensis)
The snake looks rather spindly and delicate, but don’t let its looks fool you. It lives in a god-forsaken desert and it can move across the treacherous shifting sand with blazing speed.
Aww…poor little guy lives in an enormous desert
Speaking of which, how does this animal live in such lifeless devastation? Even in the dry dunes of the Namib, life thrives on our glorious planet! Like Grant’s golden mole, the sand racer eats tiny arthropods, lizards, and rodents which make their home in the sparse scrublands along the rim of the dunes or even upon the dunes themselves (the snake clearly manages to traverse this dry sea). The snake is mildly venomous (to us—the venom works better on small prey).
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)
Sand Cat Kitten (Felis margarita) born at Zoo Brno
We all know that cats have mastered internet popularity. Whether through adorable antics on Youtube, elaborate pun-filled digital images, or just general grumpy demeanor, the felids have demonstrated an unparalleled ability to thrive in today’s new media environment. Therefore, to please the cat-loving legions of netizens, I am dedicating today’s post to sand cats (Felis margarita), which are small cats which live in the deep deserts of North Africa, the Middle East, and southwest/central Asia. Also a trio of sand cat kittens was just born in Zoo Brno in the Czech Republic, so expect this post to get super cute!
A sand cat hunkering down in the deserts of Saudi Arabia
With short legs, a stout body, and a long tail, sand cats are among the tiniest of cats. Full-grown adults weigh only 1.35 to 3.2 kg (3.0 to 7.1 lb). Sand cats live in discontiguous ranges—so they are separated into several subspecies which are evolving in different ways. The tough little cats thrive in the deepest hottest deserts—the Sahara, the Rub’ al Khali, the Lut—where they live without water by surviving on the moisture in their prey. Like all cats, they are formidable predators, but their hearing is superior even to other felids: sand cats have huge highly-refined ears which are capable of hearing tiny burrowing animals moving deep beneath the sand. They survive on rodents such as jerboas, gerbils, and spiny mice, but they also hunt small birds and reptiles (and they are known as a particularly adept killer of snakes). Sand cats have heavy fur on the pads of their paws so they can run across burning desert sands. They co-opt the abandoned burrows of other desert creatures as their own to hide from the scorching daytime heat.
A sand cat with a snake
Sand cat populations are diminishing in the wild as human development encroaches on the edge of their habitat–but the true depths of their hellish deserts are places where humans are unlikely to build condominiums, so sand cats are merely listed as near-threatened. Until recently sand cats did not do well in zoos, and they are a somewhat unfamiliar animal. Because they are used to profoundly arid climate, they would die of respiratory infections when brought into humid locations. Today zookeepers know to keep their sand cats in dry arid enclosures—which mean the creatures are beginning to do much better in captivity. In 2012, the first captive sand cat kittens were born in a zoo in Israel, and this year three kittens were born in the Czech Republic. Look at how adorable they are (well, assuming you are not some timid burrowing desert creature).
Sand cat kittens at Zoo Brno (credit: Zoo Brno)
The mythological monster, Cerastes
Cerastes was a monster from Greek legend with the body of a snake and horns like a bull or ram. According to legend, the monster would bury itself in the sand except for its horns, which protruded from the ground. Other creatures would approach the mysterious horns to see if a carcass was nearby, whereupon the Cerastes would emerge from the earth and devour the victim. Although the creature sounds fanciful to the point of absurdity, it found a home in many medieval bestiaries, and no less a person than Leonardo da Vinci wrote about it.
The Horned Desert Viper
The legend however, does have a kernel of truth. The North African horned desert viper has small horn-like appendages above its eyes and it hides in sand to stalk its prey (plus the snake already blends in with the desert due to camouflage coloration). The desert viper only measures 60 centimeters (about a foot) in length, so it is hardly swallowing large beasts like the mythical cerastes! Yet the desert viper is also acutely toxic—not to mention, real– and a mere 40 ml of venom are enough to kill a person. Fortunately the desert viper is a good-tempered snake and tends to warn victims before striking by rubbing its scaly coils together to make a hissing/sawing noise. The resemblance was enough however that taxonomists gave the little viper the scientific name Cerastes cerastes.
The Horned Desert Viper (Cerastes cerastes)
Wadi Al-Hitan, Egypt
In the desolate desert 150 kilometers southwest of Cairo there is a fearsome arid valley (wadi) of cliffs, carved buttes, and sandblasted erratic boulders. The bleached landscape has an otherworldly emptiness as though it were located on a lifeless alien planet, though if you look closely, the desert is filled with austere furtive life like dorcas gazelles, tiny sand colored lizards, cobras, scorpions, and fennec foxes. The name of the place is even more otherworldly—“Wadi Al-Hitan” which is Arabic for “valley of the whales” and although the great smooth rocks buckling out of the sand might momentarily be taken for the backs of huge whales, the utter absence of the ocean (or of water of any kind) makes the name seem fanciful. The nearby Mount Garet Gohannam (which means mountain of hell because of the way it glows like flames at sunset) seems to be more aptly named.
Whale fossil at Wadi Al-Hitan
However the name of Wadi Al-Hitan is remarkably literal–for the valley contains the remains of hundreds of huge ancient cetaceans which died in the Eocene and were fossilized in the yellowish sandstone. Forty million years ago the valley was a marine lagoon. Although the remains of numerous sirenians, sawfish, sharks, rays, sea turtles, marine crocodiles, sea snakes, and even swamp dwelling moeritheriums have been discovered in the wadi, the valley takes its name from the most spectacular and numerous fossils which belong to four different species of primitive whales. The most commonly discovered fossils belong to Dorudon, which was 3-5 meters long (9-15 feet) and fed on fish and mollusks, and to Basilosaurus, which was 15-22 meter (50-72 foot) and fed on everything else in the ocean.
Basilosaurus was first discovered in Louisiana in the early 19th century. Its immense size and serpentine form initially convinced naturalists that it was a marine reptile and they misnamed the creature Basilosaurus (which means “king lizard”). The mistake soon became obvious and Basilosaurus was classified among the Archaeoceti, a paraphyletic suborder of the cetaceans, however the giant kept its dinosaur name. Different species of Basilosaurus flourished in oceans worldwide during the wet, tropical Eocene and, even though they were obviously very adept at ocean living (indeed rising to the top of the food chain) the creatures betray vestiges of terrestrial living which modern whales have entirely dispensed with. Not only do Basilosaurus fossils have teeth and jaws which retain reatures from their artiodactyl ancestors, they also have tiny vestigial back legs a mere half meter in length (which would scarely help a 22 meter animal get around). Additionally Basilosaurus was different from modern whales in that it probably moved with eel-like horizontal thrashing of its long tail (modern whales move their flukes vertically). Basilosaurus probably did not dive very deeply, but moved about near the surface of the oceans hunting for smaller marine animals.
Basilosaurus from “Life in the Ancient Seas Exhibit” at the Smithsonian Institution, National Museum of Natural History
Although Wadi Al-Hitan was discovered by Europeans in 1902-1903, some archaeologists and anthropologists have speculated that it was known long before that and have been irresistibly drawn towards comparing basilosaurus with the giant crocodiles and earth spanning serpent gods which populate ancient Egyptian cosmology.
Detail from painting (Life in the Ancient Seas Exhibit: Smithsonian Institution, National Museum of Natural History)
Pink Fairy Armadillo (Chlamyphorus truncates)
There are twenty extant species of armadillos–new world placental mammals covered with armored plates. The smallest of these armored creatures is the Pink Fairy Armadillo (Chlamyphorus truncates) which is only 9-12 centimeters in total length (about 4 or 5 inches). The diminutive creature weighs slightly more than 100 grams when mature and inhabits the central drylands of Argentina. It has multiple hard ring-like plates of delicate pink which it can close into a box form for protection (although its first defensive strategy is to dig into the ground). The animal has tiny eyes and a torpedo-like head for pushing into the sand. The portions of the Pink Fairy Armadillo not covered with plates are covered in dense white fur. Like the golden mole of Namibia, the pink fairy armadillo is a sand swimmer: the little animal agitates the fine, dry sand with its powerful claws and literally swims through the turbulence with its hard bullet shaped body. The armadillos are also like the golden mole in that they can lower their metabolism to levels unheard of among other placental mammals. However armadillos are not closely related to the golden mole—or indeed to any other placental mammals other than fellow Xenarthra (the sloths, armadillos, and anteaters). South America spent a long portion of geological time as an island and the mammals there had a long time to develop on their own. It is still not known whether Xenarthrans like the Pink Fairy Armadillo are truly Eutherians or whether they are the descendants of the ancestors of the Eutherians (sorry: the language of cladistics does not lend itself to eloquent explanations and all of the names sound like they come from a far-away planet—for example “Xenarthrans”).
I would like to tell you more about the Pink Fairy Armadillo, but I am unable to do so. Since it lives underground, the animal is rarely seen in the wild. It is even more unusual in captivity where it does not long survive the shocks and stresses of zoo living (additionally it seems unable to live on anything other than local invertebrates). This is unfortunate as it is believed that the Pink Fairy Armadillo is struggling in the wild. It is presumed to be declining in numbers–a victim to habitat loss from human activity. I used wiggle words like “believed” and “presumed” because nobody really has any idea about the actual populations of Pink Fairy Armadillos.
In the absence of real information here is a little gallery of Pink Fairy Armadillo artwork. Enjoy these pictures, it is profoundly unlikely you will ever see a real Pink Fairy Armadillo in the real world (which is sad because I find them curiously endearing). I particularly like the cartoon of the Pink Fairy Armadillo dreaming of transcendence into a mythical fairy being.
Drawing by Frohickey
Digital Artwork by Loba Feroz
Art by Guertelmaus
Sculpture by Michelle de Bruin
Cartoon by Blade Zulah
Grant's Golden Mole (illustration from Michigan Science Art)
Yesterday I spent some time describing the Namib Desert (as well as giving a brief overview of the entire nation of Namibia). I did this not just because Namibia strikes me as one of the most striking landscapes on earth, but because the harsh habitat is home to a profoundly strange mammal, Grant’s Golden Mole (Eremitalpa granti), a solitary, nocturnal predator of the Nagib Desert. Grant’s golden mole lives primarily in the Namib Desert but ranges as far north as Angola and as far south as the arid dunes of South Africa.
The golden moles are already strange animals. The name “mole” is a misnomer: golden moles are not closely related to the true moles (which are insectivores) or to the marsupial moles of Australia. Their taxonomical classification is presently unclear but they seem to be most closely related the tenrecs, a group of insect eating primitive placental mammals. Tenrecs and golden moles both have unusual dentition (a critical feature to the taxonomist) and possess cloacas like birds. It has been speculated that tenrecs and golden moles are closely related to the first placental mammals, but this may be a mistake. It is also possible that the tenrecs resemble the ancestral placental mammal of long ago whereas golden moles have evolved features which uniquely suit their desert environments.
Van Zyl's Golden Mole (Cryptochloris zyli) photo from "Professor Paul's Guide to Mammals"
Grant’s golden mole is a particular anomaly since it is so profoundly suited for desert living (which may have to do with the great age of the Namib Desert). Grant’s golden mole does not make permanent burrows but literally swims through the sand. The creature has powerful claws for digging which have almost some to resemble “sand flippers”. It can move swiftly underground and detect its prey (termites, scorpions, and lizards) through its profoundly acute sense of touch. Its eyes have become vestigial and are covered with both skin and fur. Because it burrows through fine particles of sand, its coat is incredibly fine and dense, its nose is a leathery wedge, and its ears have shrunk to tiny, tiny openings.
Grant's Golden Mole
Grant’s golden mole does not build burrows so it is not known how or where it raises its young. Because water is so scarce in the Namib Desert, the golden mole does not drink: its kidneys are hyper efficient. It also does not regulate its temperature in the manner of other mammals and it is capable of dropping into a suspended state during the days (when it digs deep down into the oxygen poor sand). Grant’s golden mole requires large swaths of sandy desert for hunting. It lives only on the shifting dunes. With such a lifestyle you would think that it has escaped trouble from humankind, but you would be wrong. The giant sand mines of Namibia are eating into its habitat and it is preyed on by feral cats. In so far as we know anything about its numbers, we believe it is threatened. Even in one of the most inhospitable places, humans are making inroads.
Grant's Golden Mole after a Successful Hunt (Minden Pictures)
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