Category Archives: Freshwater Life

Water Into Wine

The Son of Man. The Lamb of God. The King of Kings. The Knave of Hearts. The Sultan of Swat. Jesus of Nazareth, also known as the Prince of Peace, and in America, the God of War, was said to perform a string of miracles at the beach town of Tiberias on the Sea of Galilee in Israel. One of them involved catching a great deal of fish with one net. Another, feeding several thousand people with very little food. And yet another involved walking on water to meet a boat full of his disciples, who were caught in a sudden storm.

"Duuuuude! Watch out for that waaaaaaave!"

Now, Clarke’s Third Law states that “any sufficiently advanced technology is indistinguishable from magic.” So nowadays, the miracle of the modern fishing industry, with its deep-sea trawlers, 150-mile longlines, and space-age tracking and echolocation technology, ensure that our nets can catch hundreds of thousands of fish at a time. (Though not for much longer.) And genetic engineering, bolstered by mechanized farming and artificial fertilizers, ensures we can feed the multitudes. (Though not for much longer.) But biologically and technologically speaking, how miraculous is it to walk on water?

Stroke! Stroke! Stroke!

Not very, if you’ve got the right tools, and the right size. The most classic example of animal locomotion on the water’s surface is the water striders, or water skaters, or water scooters, or any of the other collective names for these 500 species of insects that make up the Gerridae family. They are hunters that use surface tension to their advantage; where prey might swim, they float like a bubble. Their short front legs are for grabbing, their middle pair for “skating,” and the hind pair act as rudders. The secret to their unsinkability is the hydrophobic hairs on their legs. Each leg is covered in thousands of fine filaments called microsetae that spread the weight out on the water’s electric “skin” of surface tension, and the grooves in each filament trap tiny air bubbles which add to their buoyancy. So powerful is the effect that a water strider could carry fifteen times its own weight and still remain afloat, and a few species have even adapted to walk the waves of the open ocean.

The ability to walk on water kind of goes to their heads.

But it’s not only insects that have the ability to walk on water. A few reptiles have also evolved to stay high and dry. And more advanced insects have discovered not just how to walk on water, but how to turn water into wine.

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Five Feet High and Rising

The creek behind my uncle’s house here in Western Ohio is flooding; normally a laconic and nameless little tributary with quietly dipping mallards, last night’s thunderstorm and rapidly melting snow has raised the water level almost twelve feet and transformed it into a swollen, churning torrent. As I sit here watching the lawn furniture and Fisher Price playsets rush downstream, I thought it’d be appropriate to talk about animals for whom floods are home.

I’ve written before about the flooded forests of the Amazon basin, the Amazon river dolphin in particular, but it’s worth another visit. The Amazon is sometimes referred to as the River Sea, and the reason why becomes clear when the water level rises 30 feet and covers three times its already substantial area. During the Spring floods, a gondola navigating the trees in the rainforest might come upon a pair of giant otters chasing each other through the water, or glide into a mysterious pool of shimmering gold which, on closer inspection, turns out to be a school of piranhas. Here in the varzea, the underwater forest, the Amazonian manatee does the dead man’s float while grazing on submerged meadows, and the anaconda rolls like water boiling. And if you’re lucky, you may find the dragon of the Amazon: the arapaima.

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His animal collections from the Amazon rainforest made lesser zoologists weep. He traveled into the jungle with the finest scientific equipment of his time, each instrument cradled in its own velvet-lined box. Thomas Jefferson once invited him to the White House, just to bask in his genius. Where ever he walked, he got a standing ovation. He was called “the greatest scientific explorer who ever lived”… by Charles Darwin.

He was… the most interesting naturalist in the world.

Ich weiß nicht immer Bier trinken, aber wenn ich das tue, ziehe ich Zwei XX.

That Alexander von Humboldt does not enjoy household name recognition is a testament to American scientific illiteracy. During the 19th century, he enjoyed rock star status around the world for his contributions to geology, meteorology, and zoology, and for his books recounting his adventures in the jungles of Latin America. Edgar Allan Poe dedicated his last poem to him. “Every scientist is a descendant of Humboldt,” said Emil du Bois-Reymond, the father of neurology. “He is the true discoverer of America,” said Simón Bolívar.

Though the word “ecology” didn’t exist yet, Humboldt was among the first scientists to view nature as a holistic, interconnected web, and as such he studied everything about a place’s environment wherever he traveled, from barometric pressure to soil samples. Scientific data, not religion or ideals, ruled his discipline to a degree never before achieved in field biology. During his long career, he advanced the science of volcanism, tested the bioluminescent properties of jellyfish and the electrogenerative powers of electric eels, dissected the larynx of the howler monkey, realized the use of bat guano as a fertilizer, figured out the correlation between plant species and altitude, discovered ocean currents and weather patterns, made the only reliable map of South America at the time, and met such species as the Humboldt penguin, the colossal Humboldt squid, and a subspecies of Amazon river dolphin living in the Orinoco river, Inia geoffrensis humboldtiana.

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Big Baby

At first glance, Pseudis paradoxa looks like the most normal frog in the world. It’s green, it lives in the water, it buries itself in mud, and it eats flies. Nothing particularly unusual about it. Until you meet its monstrous offspring.

That’s the P. paradoxa tadpole. And this is the adult and the tadpole next to one another:

The tadpole is almost four times larger than the adult; while adults measure about 3 inches long, their offspring can grow to 10 inches long. And there’s the mystery behind the Paradoxical Frog. There are invertebrates in the world which are larger in their larval stage, metamorphosing from chubby caterpillars to svelte butterflies. But this is the only vertebrate whose offspring is larger than its adults, and we have no idea why. And as long as science can’t yet explain it, why not indulge the urge to irresponsibly hypothesize?

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Yesterday’s post was dedicated to spider silk and many of its wondrous uses. Today’s post is about the most wondrous use for spider silk of all. But first, an interlude to talk about comic books.

You know how Spiderman uses his synthetic webbing for all sorts of purposes beyond “slinging”? Sure, there’s the “getting around” webbing, but he can also gift-wrap criminals, or use the “silk” as a projectile glue-bomb that blinds them. He can spin webbing that acts like an airfoil or a parachute. All of these are things that real spiders can do with the seven or eight types of silk for which they’re equipped. But could a spider use his silk to make baseball bats, trampolines, dummies, bandages and slings, or even watertight domes that would trap air so that he could breathe underwater?

Yeah, about that last one.

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Buried Alive

You will probably never see a purple frog. In order to see a purple frog, you very much have to be in the right place at the right time. The place: a tiny fraction of a tiny but biologically rich mountain range in Southern India called the Western Ghats. The time: the summer monsoons. If you come to the Western Ghats in October, or go anywhere else but that few hundred square miles of wet plateau in June, you and the purple frog will miss each other entirely.

It is a great round blob of an animal, the purple frog, with a hard, beak-like nose for breaking into termite tunnels. Its eyes seem too small, its stance pigeon-toed, its call sounds like that of a chicken. It is such an unusual animal that it’s surprising it wasn’t discovered until 2003. The reason it remained hidden so long is that the purple frog is subterranean, burying itself alive for most of the year until it hears the drumming of the monsoon rains on the earth above, and clambers up to the surface to mate.

The Art of being Buried Alive is not an easy one to master. It requires you to slow your metabolism to a crawl, to live as if hibernating, but without being asleep. It is a self-imprisonment during which you cannot dare to plan your escape, or you will go mad. I imagine you can’t think at all. The purple frog is not in complete stasis: it hunts termites, its heart beats. But mainly, it squats in the dirt and listens. Who knows if the purple frog’s mind remains safely dreamless and null as it waits in the earth. Perhaps it does nothing but dream.

This waking hibernation has a name: estivation. For most animals that employ it, estivation happens during the dry summer months, but the Indian monsoon season starting in June makes the purple frog’s cycle unusual. Consider the lungfishes, those ancient and air-breathing fish whose shallow ponds which, for much of the year, do not exist. That’s right: there is a fish that can survive in a lake with no water. During the dry season, the lungfish buries itself in the mud, coats itself in a mucus cocoon, slows its breathing rate down to next-to-nothing, and estivates. It is awake. It waits for rain.

It’s been a long, dry summer.


Yesterday I talked about the animal that gets the most sunlight. Today, one that gets none at all.

It’s the Olm, also called the Proteus. It’s an amphibian endemic to the subterranean caves of the Balkans, and being cave-dwelling, it has no use for eyes or pigmentation. Its body has become serpentine, to incorporate more touch receptors. Its tiny feet, instead of having the four toes like most amphibians, have only three toes each on the front limbs, two on the hind. Like the axolotl, it retains neotenic features such as external gills: it is a dragon embryo surviving in the dark, an infantile troglodyte.

With its acute sense of smell and touch, the olm gets along just fine in what, for us, would be the equivalent of a sensory-deprivation chamber. Hundreds of yards beneath the Earth’s surface, the water temperature remains constant, there is almost no sound, and the olm has no predators to worry about. But then, there is very little food. Barring tiny crustaceans and snails, as well as its own bacteria-laden skin molts, there is almost nothing to eat in a world so far removed from the sun. Instead of shutting down its life functions like the water bear, the olm has gained the ability to go up to ten years without eating. With a lifespan of up to 70 years, and perhaps even 100, an unlucky olm may eat only a few times in the course of a century. But centuries do not exist here: where the olm lives, there are neither years, nor seasons, nor hours, nor day and night.

If outer space is a vacuum, there are places in inner space that are as close to oblivion as possible, and there is a vertebrate uniquely adapted to thrive here in this near-nothingness beyond light and time – slithering, starving, waiting for rains it will never know to wash down a few crumbs of life to eat. As an atheist, I think of Earth as the closest thing to Heaven. But there is also an underworld here, like the atheist’s afterlife: noiseless, blank, without time or change or meaning. And here, too, life persists.