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Mozambique Diary: Amphisbaenians

Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Having drawn the short straw at the phenotypic lottery I have always felt a special kinship with creatures that most people dismiss as too small, too creepy, too unattractive. Because these are (I tell myself) the hallmarks of the truly interesting organisms, ones that have followed the less-trodden paths of unusual specialization, remarkable adaptations, evolutionary ingenuity.

One such organism, about the existence of which I learned as a young child from an old zoology textbook, was Bipes, an amphisbaenian. It was a chimeric, strange creature, with the appearance of a pink snake, but equipped with a pair of shovel-like legs at the front end of its long body. There was a striking resemblance between that creature and a picture of a dragon that I had seen in the illustrated edition of the Old Testament from my Sunday School (which, incidentally, offered its classes on Monday nights), and I was instantly hooked.

Although it looks like a soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Although it looks soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Amphisbaenians are reptiles, but so unusual that for the longest time they were considered a separate order of these animals. For one, they look nothing like a vertebrate – the last couple of times that somebody brought me an amphisbaenian they were under the impression of having collected an earthworm (unlike Bipes, most species are legless.) Their annulated body is usually pink or covered with irregular, white and dark blotches, a clear indication that these animals don’t care about how they are perceived by others. And for a good reason – why bother with the looks if your entire life is spend underground and you yourself are blind. Better to invest the energy that would have been spent on the irrelevant appearance into things such as a thick skull and powerful thoracic muscles that will allow the animal to push effortlessly though the soil in search of prey.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

Recent phylogenetic studies revealed that amphisbaenians are not a separate, primitive order of reptiles, but rather a highly derived, supremely modified lineage of lacertiform lizards. It is very likely that the next step in this transition to a subterranean lifestyle was the complete loss of limbs and girdles, a dramatic reshaping of the skull, the loss of eyelids and, eventually, the emergence of a brand new group of animals, the snakes. In fact, the most basal (primitive) snakes, the Typhlopidae and other related families, look remarkably like the amphisbaenians.
A few days ago I was in the southern part of Gorongosa, checking out sites for the second biodiversity survey of the park, and there, in a dry, crumbling log, I found a beautiful little amphisbaenian, Chirindia swynnertoni. This species is rarely seen, and thus I promptly followed a recommendation of a field guide to amphibians and reptiles of East Africa: “Anyone finding a worm-lizard [amphisbaenian] should take it to a museum.” I still haven’t had the heart to preserve it for the Gorongosa Synoptic Collection, and instead I have been watching it for days, transfixed by its amazing ability to squeeze into the hardest soil with the body that looks like an overcooked string of pasta, and with a baby-pink face of a newborn. It has been feeding on termites and ant larvae, crushing the insects with its tiny yet powerful jaws. And I find it fascinating (and somewhat rewarding) that from so seemingly unassuming a beginning came a lineage of animals that has terrified the human psyche since the time of Eden.

Gorongosa amphisbaenian (Chirindia swynnertoni)

Gorongosa amphisbaenian (Chirindia swynnertoni)

Mozambique Diary: Shooting bats

Leaf-nosed bats (Hipposideros sp.) in a cave of Cheringoma Plateau, Gorongosa National Park.

Leaf-nosed bats (Hipposideros sp.) in a cave of Cheringoma Plateau, Gorongosa National Park.

My entire last month was a blur of hectic activity, related mostly to the opening of the E.O. Wilson Biodiversity Laboratory in Gorongosa National Park. This kept me from updating the blog, but it was definitely worth it – the Lab is a fantastic facility that will serve as a research base to current and future scientists in the park, and as a center of advanced biodiversity education for Mozambican students for years to come (I just finished teaching its first African entomology workshop there, and it was great.) We are also creating the Gorongosa Synoptic Collection, which has the ambitious goal of documenting, over the next 15-20 years, all (or at least as much as physically possible) multicellular diversity of the park – I will try to post frequent updates from this effort. In the meantime, I would like to invite all biologists to come and work in Gorongosa – there is an entire universe of unexplored life out there, waiting to be studied and saved. Contact me if you are interested – Gorongosa wants your research projects, and we will help you make them happen.

Slit-faced bat (Nycteris cf. thebaica) from Gorongosa and a sonogram of its echolocation.

Slit-faced bat (Nycteris cf. thebaica) from Gorongosa and a sonogram of its echolocation.

One of the many benefits of having a permanent and safe logistical base in a place as biologically rich as Gorongosa is that I am not afraid to bring and leave behind my expensive high tech gear, and experiment with it. For months I had been dying to try out my high speed photography system, and finally was able to use it last month to shoot flying bats in the comfort of our lab. Now, bats have been photographed in flight by many, and the technology to do so has existed since at least the 1980’s. But, as far as I could tell, few had tried to take images of flying bats using the white background technique, made popular by the Meet Your Neighbours project, and I really wanted to try it.

An orange form of a Horseshoe bat (Rhinolophus landeri) from Gorongosa and a sonogram of its echolocation.

An orange form of the Horseshoe bat (Rhinolophus landeri) from Gorongosa and a sonogram of its echolocation.

The setup for photographing bats in flight will be familiar to anybody who has ever worked with high speed photography: I used an external, very fast shutter (6mS response time, 10-50 times faster than the shutter in a typical SLR) mounted on a Canon 7D with a 100mm macro lens, triggered by two intersecting laser beams, and with four Canon flash heads that provided the illumination. Cognisys is a company that sells turnkey solutions for high speed photography, and their excellent StopShot system is what created the basis of my setup. The tricky part was to create a stage where the bats’ flight path was relatively narrow, allowing me to illuminate it properly. Last year I photographed bats in a cave, which was relatively easy, but gave me little control over the lighting. I needed to restrict their movement better, and decided to bring a large diffusion box that I would then turn into a flight chamber for the bats.

The box was about 1 m (3 ft) long, giving even the largest Gorongosa species ample room to fly. On the sides of the box I cut out two small windows (covered with thin, clear Perspex) that allowed the laser beams to go through. The front of the box had to remain unobstructed to the lens, but something had to stop the bats from flying out; I ended up using a large piece of thin glass (and had to adjust the flashes so that they would not reflect off the glass). But somebody had to put the bats in there, and it was not going to be me (one word – rabies!)

Leaf-nosed bat (Hipposideros caffer) from Gorongosa and a sonogram of its echolocation.

Leaf-nosed bat (Hipposideros caffer) from Gorongosa and a sonogram of its echolocation.

Luckily, I got help from Jen Guyton, a Princeton graduate student and a bat specialist, who is working on her Ph.D. in Gorongosa. Since capturing bats to get samples of their DNA (or rather the DNA of their prey) was part of her nightly routine, Jen was able to bring live bats to my studio and control them while I took the photos. Once all the technical kinks were ironed out, the system worked like a charm – in a few minutes I would get multiple shots of each bat, and then the animal was removed from the chamber unharmed.

A studio setup for photographing bats in flight: (1) Cognisys high speed shutter, mounted on Canon 100mm lens; (2) a laser and a laser beam sensor (an identical but vertically reversed set is positioned on the opposite side of the box).

A studio setup for photographing bats in flight: (1) Cognisys high speed shutter, mounted on a Canon 100mm lens; (2) a laser and a laser beam sensor (an identical but vertically reversed set is positioned on the opposite side of the box).

But some species turned out to be more difficult than others – members of the family Molossidae (my favorite bats) are not able to lift off from horizontal surfaces and thus could not fly in the box. Next month I plan to photograph them in the wild by combining this system with a UV light – I hope that the bats will be attracted to insects coming to the light (which they often are) and sooner or later will hit the laser trigger. Watch this space to see if it worked.

One final note – don’t try any of this at home! Nobody but professionals, vaccinated against rabies, legally permitted, and fully trained to handle live bats should ever attempt catching these animals. If you are interested in photographing bats, get in touch with a mammalogist at a nearby university or a conservation group that works with these mammals, and they may be able to help you. They are an awesome group of animals, but don’t risk their or your own life. Having seen Gorongosa bats’ unbelievably sharp, lyssavirus-carrying teeth in action, I now think of them as flying vipers – cool, beautiful and fast and, potentially, very deadly.

A grey form of the Horseshoe bat (Rhinolophus landeri) from Gorongosa

A grey form of the Horseshoe bat (Rhinolophus landeri) from Gorongosa

 

Mozambique Diary: The House of Spiders

A guest post by Edward O. Wilson

The skeletal remains of the Hippo House, once a busy restaurant and observation point.  Orb weaver (Nephilengys cruentata) from the Hippo House.

The skeletal remains of the Hippo House, once a busy restaurant and observation point.

Each spider in the Hippo House was sheltered in a tubular retreat, a behavior typical of all species in the genus Nephilengys.

Each spider in the Hippo House was sheltered in a silken, tubular retreat, a behavior typical of species in the genus Nephilengys.

At the end of a long rutted road in the park sits a conspicuous artifact in the midst of wilderness. Built in 1970, the Hippo House was the vantage point, the antigo miradouro, from which well-heeled tourists, cool drinks in hand, watched wildlife herds as they grazed over the vast floodplain grassland below. Today the herds are back, but the house is a seldom-visited ruin. During the Mozambique civil war, almost all the buildings of Gorongosa National Park were torn down or blown away, leaving behind a few remnants scarred by bullets. The house had been reduced to a shell of its original self.

When I first visited the Hippo House, Mozambique was in the middle of the winter dry season. Other than along the watercourses, the vegetation of Gorongosa was brown and withdrawn. Insect life was still abundant, but harder to locate. I had been told that spiders, big ones, were abundant at the house, but I was quite unprepared for what I found. The interior of the ruined building was powder dry. Its floor, stanchions, and ceiling were windblown and coated with dust. No vegetation reached in from the outside, and except for a few small geckos resting on the pillars, there was no immediate sign of life of any kind. Instead, torn webs and long single threads of silk dangled from the ceiling like ghostly decorations in a haunted house. They swung gently back and forth in the occasional light breeze. No other movement or sound came from the seemingly empty space.

An unlucky katydid that flew into a web under the Hippo House is immediately killed and wrapped in silk by a female orb weaver.

An unlucky katydid that flew into a web under the Hippo House is immediately killed and wrapped in silk by a female orb weaver.

Where were the spiders I expected? Not one could be seen. But I knew they must be there someplace, alive, perhaps watching us. The idea of a hidden arachnid horde ready to rush out made me uneasy. Soon I saw something else: round objects plastered onto the ceiling. They were dusty and silent. My companions and I picked up a stick lying on the ground outside that was long enough to reach the ceiling, and tore two of the pouches apart. They proved to be silken egg pouches, undoubtedly made by spiders but now dry and empty; we were obviously not in the breeding season. The spiders themselves stayed hidden. Where were they? I grew more apprehensive.

We saw other, much larger, oblong pouches scattered over the rough eroded ceiling. At the tip of each was a circular entrance opening to a hollow interior. Using a flashlight and looking straight down the chamber, we could see what lay within. There at the rear of each pouch crouched a large spider, facing outward, its fangs, eyes, and the front of its tightly bunched legs visible. I wanted to see a specimen well enough to identify it, but hesitated. I was, to be frank, afraid of these crouched and waiting spiders. I suffer from mild arachnophobia. This spooky place was the setting of an arachnophobe’s nightmare.

The golden orb-weaver (Nephila senegalensis) is one of the largest spiders of Gorongosa. Its name comes from the beautifully golden coloration of its silk.

The golden orb-weaver (Nephila senegalensis) is one of the largest spiders of Gorongosa. Its name comes from the beautifully golden coloration of its silk.

We selected one of the pouches and poked at it in and out, but the spider stayed tight inside. One of my companions then took charge. He tore open the pouch and shook the inhabitant out into a transparent plastic bag. At last I could see what had lain within. The spider was heavy-bodied, the size of a thimble. When it suddenly spread its spiny legs, its width almost tripled.

I had solved the mystery of the spider house, at least in theory. The creatures in the silken bags were orb weavers, members of the spider family Nephilidae, called golden orb weavers, and, I later learned from an arachnologist, the species is Nephilengys cruentata. Some species of nephilids and the closely related araneids hide in retreats next to their webs; others remain in the centers of the webs. But how could there be so many spiders of this one species crowded together? Why are there no other creatures of any kind? The explanation I believed to be immediately clear. The floor of the lower level of the spider house is a layer of concrete. The interior is abnormally dry. Because the lower level cannot be invaded by any vegetation, few if any other forms of insect or arachnid life can live there. Yet flying insects undoubtedly fly through the wide-open space of the lower level, in through one side and out the other. A few might settle there to rest. The fate of most or all is the same: spider food.

Orb weaver (Nephilengys cruentata) from the Hippo House.

Orb weaver (Nephilengys cruentata) from the Hippo House.

My imagination was roused by this bizarre little world, but more so by my own reaction to it. When I took the captured spider back to Chitengo Camp, I found I was unable to make a specimen of it. That would mean fishing the monster out of the cellophane bag and working it into a bottle of preservative. So I simply opened the rear window of my room and dumped my captive live onto the ground below, where it would at least have a chance of making its way to a tree or building and spinning a new silken retreat.

I remember vividly the incident that made me an arachnophobe. I was eight years old. It was late summer, and I was exploring a vacant lot near our house. There were several full-grown female orb-weaving spiders in the high weeds, likely the common garden spider (Araneus diadematus), sitting in the center of their webs. I could not resist getting close enough to see all the details of one spider’s body. When I was about a foot away, it began to jerk back and forth in a menacing manner. I thought it was preparing to jump out and onto me. I ran. If that were not bad enough, I soon afterward saw a movie, the name of which I have long forgotten, in which a man is trapped in a cave. Blundering around, he becomes tangled in spiderwebs that are hung all around. Spiders, really big ones, climb down toward him, and . . .

Aversions and phobias of this kind, with the latter an extreme response causing panic and cold sweats, can be imprinted with as little as a single brief episode. They are rarely caused by a frightening experience with a knife, a gun, an automobile, or any other modern contrivance that can injure or kill. On the other hand, they easily and quickly follow a frightening experience with one of mankind’s ancient perils: snakes, spiders, wolves, heights, running water, and closed spaces. During millions of years of human prehistory, it has paid in a major Darwinian way to have quick, decisive response to the things that can kill you.

So I have forgiven myself for the wavelet of fear and revulsion I felt about the harmless denizens of the spider house. Let me make further amends by stressing that people are mostly safe amid what remains of living nature. We conquered the man-eaters long ago by destroying almost all of the big predators willing and able to hunt humans. They survive in our stories and in our legends of monsters. We imagine them silently emerging from caves and swamps, easing up from unexplored depths of the sea, or drifting down unseen from above. Walk into or swim in any wild habitat remaining on Earth, maintain the same level of caution you would on a city street, and you will be far safer than in most urban environments. Use common sense: don’t swim with crocodiles; don’t paddleboard among seals where great white sharks have been seen; and above all, never, ever run up to a mother grizzly bear with cubs to take a better look. Your greatest risk in the wild is from insect-borne disease—malaria, dengue, leishmaniasis, yellow fever—and these can be deadly if untreated. But they are transmitted chiefly among people. They can be easily avoided, and in any case pose less risk to you than the mélange of pathogens passing directly from person to person in human settlements.

The scary but harmless spiders in the Hippo House, and all the other animal species of wild environments like those of Gorongosa, are instinct-guided. They rigidly follow life-and-death routines formed during millions of years of evolution. Their lives are finely tuned and fragile in ways that are blessedly unthreatening to human beings.

Text Copyright © 2014 by Edward O. Wilson, Photographs Copyright © 2014 Piotr Naskrecki

Read more about the biological complexity and restoration of the fascinating ecosystem of Gorongosa National Park in “A Window on Eternity”, a new book by E.O. Wilson, with photos by P. Naskrecki (Simon & Schuster 2014).

Tarantulas, known in southern Africa as baboon spiders, may look frightening but are generally harmless. Their main line of defense is not their venom, but tiny urticating hairs that cover the entire body.

Tarantulas, known in southern Africa as baboon spiders, may look frightening but are generally harmless. Their main line of defense is not their venom, but tiny urticating hairs that cover the entire body.

Piotr Naskrecki and Edward O. Wilson in Gorongosa National Park, Mozambique.

Piotr Naskrecki and Edward O. Wilson in Gorongosa National Park, Mozambique.