How Would Nature Design a Diaper? Please Share!

 

Biomimicry Design Challenge, open to all!

I received an email this month from Kristin Follmer, a recent Rural Health and Sanitation Volunteer in the Peace Corps. She was stationed in Paraguay, where fresh water and sanitation infrastructure tend to be poor, and childhood intestinal infestation, primarily tapeworms and Giardia, is shockingly common (as high as 80%).

Kristin relates that education, hand-washing, construction of sanitary latrines, and protection of fresh-water are vital for controlling infestation, but there is one major obstacle: rural Paraguayans have no good solution to dirty diapers.








Diapers litter the streets to be shredded by dogs, (who find them to be a delicacy, spreading gelatinous mulch like ambrosia on the fifth of July). Kristin has found bio-inspired thinking to be useful in her work, planting trees (nitrogen fixers) around latrines to assist decomposition, and she asks if you, the reader, can come up with a bio-inspired solution to the problem.



According to Kristin, there are two main challenges to the problem. First, there is no good place to dispose of the diapers. Most families burn their trash and organic material like leaves. Peace Corps encourages people to dig a trash pit in their yards, but many families do not want to live alongside their trash when they can burn it so easily. Fresh dirty diapers don’t burn well, so some people throw them down the latrines, but that’s not a popular choice because they don’t want to their latrines to fill too quickly. Kristin’s friend, Sonia collected her daughter’s dirty diapers, then brought them into town, to be taken to a municipal dump. Another neighbor, Fulana, left the diapers with the other trash, to be burned later in the week, giving the local dogs a chance to root through and spread diaper trash around the block. Another popular dumping ground is the bottom of an isolated road, where intense rainstorms routinely washed the trash downstream.



Second, there is no running water. Most families have hand-dug wells, but no plumbing. Sonia, for example, walks to her mother-in-law’s home several times a day to draw water from the well, carrying it about 50 meters home. That may not seem far, but it takes a lot of water to cook, clean, bathe, wash clothes, wash hands, water the flowers, and drink. No one wants to add washing cloth diapers to that. Plus, a mother would need to find a place to dump the poopy water afterwards. This water, probably contaminated with parasite eggs, will likely to end up in streams where kids bathe, or create muddy puddles for pigs to wallow. One common type of parasite is transmitted from soil through bare feet, and mothers washing clothes are often surrounded by small children. And of course, it vital to protect drinking water, which most people drink from their wells without treatment.

Although it would certainly be possible for a woman to use cloth diapers, Kristin doesn’t know anyone who does. Even though a single disposable diaper costs the same as three eggs or a half-liter of fresh cow milk, which is significant to these poor families, they still prefer disposable because of the water and laundry issues. But Kristin feels that an alternative that was cheaper than disposables would be adopted quickly, as Paraguayans don’t like dirty diaper trash either.

Can you help? I think this is a great challenge, and Biomimicry can be a useful tool to address it with. My hope is that we can create a conversation around the challenge, and draw a variety of great minds in to this approach. Please send me your thoughts and ideas, and I will present updates here. Ideally, we can get some school classes to participate, so please do forward this on to any science, design, or engineering teachers you may know! Kristin says she can help speculate on the cultural acceptance of any solutions that may emerge, something that would make sense to a Paraguayan.

For those of you that have no experience tackling a Biomimicry challenge, here are some guidelines for the process. I’d recommend starting with one of Janine Benyus’ TED talks on youtube, then asking yourself, “what is the real challenge here?” Obviously, you can’t ask “How would Nature design a diaper?” Nature doesn’t do diapers. So, dig deeper. You might abstract the question to “How does Nature remove waste, or unwanted substances.” Or, “How does Nature deal with bacteria?” There is also the question of “how does Nature prevent leaks?” We want a solution that a mom would actually LIKE! You may find that you want to change the entire system, going back further than the diapers!

Next, do your research. Look for organisms that tackle these kinds of problems. You will probably want to look at AskNature.org for some of Nature’s tried and true engineering solutions. Don’t be afraid to play with ideas, no matter how strange or silly, and above all, HAVE FUN! Keep me posted along the way. Let's brainstorm together! Kristin and I are excited to hear what you come up with!

Mimicking the Mimic

Thaumoctopus mimicus, better known as the Indonesian Mimic Octopus, is one of my absolute favorite creatures. Other octopuses artfully blend into rocks and seaweed while stalking their unsuspecting prey, but the Mimic skillfully shape-shifts through a cast of bold, flashy, even frightening animals. Would-be predators retreat from a convincing deadly sea snake, a menacing lionfish with venomous spines displayed, a boldly cruising open-water stingray or poisonous flatfish, or the bullet-fast claws of the mantis shrimp. Meanwhile, a lusty male crab is fatally attracted to an alluring but murderous ‘female’ crab, and at the end of the day, our little octopus male repeats this deception on his own species, sneaking (in drag) to mate, right under the nose of a larger male. This mimic has been observed imitating at least fifteen different species.

The mimic octopus adapts to a surprising array of situations with a remarkably flexible strategy: it mimics the successful adaptations of other species. Humans, too, have hit upon this strategy: Biomimicry allows us to consciously imitate the special powers of other species, broadening our ability to adapt to novel situations. And, like the octopus, we require flexibility, thoughtful use, and speedy action (in the face of impending climate change). 

Can we mimic a species that mimics other species for a living? (If we really want to fall down a rabbit-hole, we can mimic the tiny fish that mimics the octopus mimicking other species. But let’s avoid that). What can this octopus teach us as we embark on our Biomimicry venture? And what about other species that mimic for a living? 

Octopus tool use

  
 Many organisms copy others for personal gain. Some use the strategy to avoid predation. The viceroy butterfly mimics the unpleasant tasting monarch, hoping hungry birds will pass it by. The harmless king snake mimics the deadly coral snake in bold warning coloration. Ground squirrels rub their tails with rattlesnake skin sheddings, waving them vigorously when the snake approaches: beware, I am a bigger snake.


  

Others use the “wolf in sheep’s clothing” approach to lure their prey. The Alligator Snapping Turtle opens its pitiless maw, wiggling its pink tongue suggestively like a soft juicy worm. The assassin bug masterfully plucks the strings of a spider web, imitating the spider’s struggling prey until the hunter rushes out, becoming the hunted. Parasitic larvae of Lampsilis shellfish imitate small helpless fish, inviting ingestion by larger fish. The larvae pass through to the predator’s gills, upon which they dine until adulthood.

Some species pretend to be females of other species, luring careless males in for a dangerous liason. (And yes, it is always the male who is tricked). Bolas spiders emit a chemical much like the female Psychodid moth’s sex pheromone. When the male comes in to cruise her, he flies headlong into a sticky, dangling decoy.

  Mimicry is also used to enhance reproductive success. Some males pretend to be females of their own species, allowing sneaky access to mates. Even plants have this trick down: orchids specialize in masterful imitations of female insects, luring males into elaborate acts of cross-pollination. Parasitic cowbirds use mimicry to secure quality daycare for their offspring, laying eggs that look like those of other birds. The changelings hatch in the host nest, and promptly push the native eggs overboard. The unsuspecting native mother cares for the parasitic brood as if it was her own.

By now you are probably thinking, “These species are poor examples for us! They only mimic to eat and avoiding being eaten, and to make more of themselves! We want to mimic other species so we can survive profitably and sustainably.  What can these other species possibly tell us? 

Maybe it’s true. As humans, we wish to mimic abstracted strategies to make a living that supports us for the long haul. Generally, we aren’t seeking to deceive a third party (though biomimicry can certainly take us this route if our “survival challenge” is a biotic one, such as managing malaria or preventing birds from flying into windows). In addition. we learn to mimic strategies within a single lifetime, or transmit our discoveries culturally to the next generation. Surely the octopus and the other organisms we have mentioned are going through the motions of a hardwired, if elaborate, genetic dance. How far can the octopus’ strategy inform our own need for a radically flexible adaptation, one that can shift with the prevailing winds of both the marketplace and climate change?

 In Biomimicry, it’s important to go beyond the superficial and delve deeply into an adaptation’s biology. Let’s do that with our Mimic Octopus: no, it does not learn its duplicitous trade from a caring parent or teacher. But it is deucedly intelligent nonetheless, capable of advanced reasoning and even self-awareness. Perhaps it acquires its methods the hard way: through a short lifetime of trial-and-error. 





The octopus brain is small, no larger than that of a lizard (pretty remarkable, considering that of its’ clammy relatives have no brain at all). Researchers like “relative brain size” as a comparative measure of intelligence across unrelated species. This puts the octopus around the level of a komodo dragon. But wait. It turns out that fully three-fifths of the octopus’ brain cells reside in its arms…along with taste buds and photoreceptors remarkably similar to those in our eyes. Their whole body is an inside-out decentralized brain, with sensory organs built right in! If an arm is detached by a predator, it will still attempt to hunt and grab prey, stuffing it greedily to where its mouth once was. Octopi seek and store tools for later use (they plan suits of armor and doors for their dens), have distinct moods (red for rage) and capricious whims (squirt the cute keeper). They even play with balls and bottles, have a sense of self (implied by their thoughtful mimicry of other species), and can solve virtually any puzzle if there is a juicy crab at the end of it. Childproof Tylenol bottles? No problem. They are notorious midnight aquarium marauders, sneaking into other tanks nearby, returning home once satiated with neighborly concern. These are the hallmarks of true intelligence, which we associate exclusively with a select cadre of long-lived, social mammals and birds.

Perhaps it is informative to ask why the mimic octopus has this advanced ability. What evolutionary function does it serve? The consensus among evolutionary biologists has been that intelligence allows members of long-lived social species to remember and differentiate one another for complex political maneuvering. Elephants, dolphins and whales, humans and other apes all fit this pattern, as do parrots and crows. Octopuses are neither long-lived nor social, and do not engage in complex political machinations.

Why, then, does their intelligence converge upon our own (convergent evolution being the development of similar adaptations in unrelated species due to similar environmental pressures)? Why does the octopus, a creature so alien to our sensibilities, whose ancestors had no brains or eyes or even backbones, have intelligence possibly rivaling a rhesus macaque?

Soft-bodied and vulnerable, the octopuses long ago gave up the security of life in shells, much like our own ancestors gave up a sheltered life among the trees, covered in protective fur, doubled over in a gut-guarding crouch. For both families, the reward has been radical expansion and access to an untold wealth of open niches. Octopuses occur across the globe, from shoreline to abyss. (Old folks in the Northwest even spin woolly yarns about the elusive Pacific Tree Octopus). The price of admission for us both has been a hat full of clever tricks.

Octopuses and their relatives have maintained their way of life for some 300 million years, while we are new to the game (less than 50,000 years). To accomplish this hat trick, the octopus has adopted the same flexible, thoughtful, situation-specific mimicking of champion species that we have only recently hit upon. It’s a brilliant strategy, and one that we are eminently pre-adapted to use. If we move quickly, we just might find Homo mimicus around 300 million years from now.

Extremophile Planet

The Red Planet

Like millions of other Earthlings, my heart thrilled as Curiosity made improbable contact with the surface of the Red Planet. The upright ape pries open another nut, I thought to myself. Our niche expands again.

The first photos from Mars look like turn-of-the-century pinhole camera images of an alien and exotic land. They suggest a window to a past, seen “through a shattered glass, darkly.” We are here to look for shards of the past, fragmentary glimpses of what once flourished here. Maybe Curiosity will tell us about life on Mars, and maybe Mars will tell us something about life on our own blue marble.

Mars appears blasted, utterly inhospitable. It’s easy to conclude that life made no start on this barren rock, that no spark ignited the complex dance of carbon. Life may be unique to Earth. But the more we learn about the Red Planet, the less ‘unique’ Earth seems to be. Like claims about humanity’s top rung on the four-legged hairy ladder of life, our place at the planetary table seems a little less secure. The boundary between us and them sidles ever closer.

First photos from Curiosi

Mt. Sharp : NASA

Mars has a lot in common with us, besides being a great home for our discarded electronics. Though its surface is now too cold and dry to support known life forms, it was once a wet place, with many of the conditions we hold sacred to life. Liquid water may still exist below the surface, and with it, simple microbes or photosynthetic bacteria.

Mars' south pole contains huge amounts of frozen water, and recent changes in craters and sediment deposits suggest that liquid water flows sporadically on the surface. Flash-flood gullies and subsurface geysers may offer a safe retreat for microbes and even simple plants, sheltering them from solar radiation. Scientists of some repute suggest that transient dark spots recorded in NASA’s fly-by imagery represent bacterial colonies. As springtime sunshine penetrates the ice, these organisms stir and photosynthesis begins. Pockets of liquid water form, protected from instant vaporization until exposed to the ruthless Martian surface. Once revealed, our cosmic brethren desiccate and blacken. 

Blasted Martian landscape

If life is a simple matter of electrified chemistry, we should find multiple births in life’s cradle. But every Earthling shares a common genetic ancestry, and it seems that the “vital spark from inanimate matter to animate life happened once and only once, and all living existence depends on that moment.” You can’t just zap the primordial soup and create life.There are a few more ingredients in our self-replicating confection.

The most fundamental is the cell membrane, collecting and concentrating life’s raw ingredients into tiny reactive beakers. Second, our inert bubble needs a spark: a source of energy to defy, at least temporarily, the laws of thermodynamics. Life must acquire energy rather than lose it if it is to find perpetual motion.

On Earth, bacteria break down molecules and consume their energy. The  methanogens eat methane and wash it down with water. Other bacteria dine on sulphur, or survive on water alone. These ancient children feed on the primal matter of Earth. These are the extremophiles, lurid “colored smears on the surfaces of rocks” that make their homes in Earth’s forsaken places: boiling sulfuric volcanic vents, lightless ocean seeps, and the scalding flatulence of explosive geysers. They are gifted problem-solvers from a time before the Sun’s power was unlocked, and rich subjects for Biomimicry. Chances are, if we find life on Mars, it will be a similar case of arrested development. In fact, our methanogens grow beautifully on simulated Martian soil. Who knows, maybe someday their extremophiles will inspire our innovations.

 

Possible water-formed gullies on Mars

On the third rock from the Sun, Earthlings went even further. By striking a flint on the now-ubiquitous green pigment, chlorophyll, they tamed fire. With each iota of light energy captured, a little green creature puffed a single breath of life-giving oxygen into the larval atmosphere, to be gobbled up by the oxidizers of this New World. They spread and puffed away, until finally, the photosynthetic bacteria produced oxygen faster than it could be locked away. Our original life-givers still quietly exhale today in the far-away acidic and saline lakes where grazing snails fail. Life creates conditions conducive to life, and so cooperation and collaboration were there from the beginning. Judging from our own planet, we might expect to find an entire interconnected ecosystem dining on light energy and methane just below the Martian surface. 

Polar ice cliffs: NASA/HiRISE Team

At some point, Earth’s inhabitants got vastly more creative still, and our evolutionary history radically diverged from the scientists’ most wildly imagined Martian fantasies. On Earth, multi-celled creatures evolved and invented sex. Today, most Earthlings scramble distinct sets of genetic information together and dole them back out in fresh combinations to their children, testing each one on our big blue lab.

Are we all Martians? Bobak 'Mohawk Guy' Ferdowsi

If we do find a Martian, what are the chances this rare mutation (life) occurred independently? Isn’t it more likely that our neighbor down the street is a sister from a different father, especially since our rovers idle at the Martian curb as we speak? Our ancient climates were similar: could life flit between them like finches in the Galapagos? A billion tons of Martian rock has surfed the cosmic current to our shores, and some microbes and even lichen can survive such space journeys. If life blew to Earth on a Martian wind, like dandelion fluff across the Pacific, the spark that binds us is still singular and special. Life remains “nothing less than the transformation of matter itself,” forging indifferent elements into a vital, self- regenerating system, the elusive perpetual motion machine. 

Such journeys evoke Columbus-era species-swaps, like Pocahontas’ descendants returning home from a life-altering vacation. Maybe all of us, from slime mold to spider to ape, are born of distant ancestors whose separated-at-birth children toil on beneath the Martian ice. You can’t help but think the ones left behind got the short end of the stick. How much more miraculous are Earth’s ecologies compared with even the richest Martian ecosystem? Where are the rainforests, with over 600 insect species in a single tree, each with a pocket penknife of surprising talents? Where on Mars will we find ten million species or more coexisting in bewilderingly interconnected networks? Where does life beget conditions conducive to life? Curiosity’s blasted vision suggests we won’t find it. “In the beginning, there was dust, and one day the great, improbable experiment of life will return to dust” and primeval cells like those we imagine on Mars will once again “spread their colored slime over the Earth, even as creatures of complexity and elegance know their last days.” Until then, let’s enjoy our vacation.

All quotes and much inspiration are from Richard Fortey’s fantastic evolutionary memoir, Life.

Team Banana

Last month, in Tlapacoyan, our team was challenged to create a better way to pack fruit and get it to Mexico City with less spoilage. Yihad Ghattas is our meticulous Colombian urban planner. Our architect, Roberto Ferrar, is from Mexico City, and I am the biologist. We start by asking what kinds of fruit are grown in the region. What are the real problems faced by the growers? We interview several locals. The range of fruit is bewildering, varying fantastically in size, durability, and requirements for ripening, humidity, and temperature. Lychee, mango, oranges, limes, grapefruits, papaya, avocado, pumpkins, mamey, sapote, guanabana, melons, and even coffee…how can we possibly come up with a solution for all these? Chucho, a former grower, tells us that the most important fruit in the region is the banana. And the Tlapacoyans are not happy about the way it is grown.

Tlapacoyan is a region of stunning beauty, beloved by its people. Here, the Rio Bobo churns forcefully through a dramatic primeval landscape of ancient figs and giant ferns, dotted with colorful orchids and bromeliads, dripping with pulsing slime molds, and laced with the intricate webs and nets of an endless array of skillful and patient hunters. Team Banana picks its way carefully through coursing streams of leafcutter and army ants to get to Bobo’s sandy, bouldered shore, framed by towering trees, and littered with the corpses of hundreds of plastic bags.

Banana bags and monoculture

Covering the penca

Over the ceaseless rumbling of the river and the deafening buzz of cicadas, Chucho tells us how to grow bananas. A single violet ‘penca’ balloons perversely from each tree. These are sequestered from insects with a transparent blue baggie, which has the added function of concentrating levels of the banana’s own ethylene, thus hastening ripening. The grower cleaves the penca from the tree with his machete, and the purple bruise fades to sickly chartreuse as the bags are peeled off and discarded, sometimes catching the air to sail off like jellyfish. The bananas are plunged into the ‘carburo,’ a kind of liquid charcoal that serves as artificial ripener, and divided into family-sized bunches. These are placed into a second baggie, stacked into cardboard boxes, and loaded onto an open truck. The trucks rumble off, in a thick cloud of diesel exhaust, toward the enormous distribution center in Mexico City. Days later, the trucks return with the boxes and plastic baggies (which the distributor does not want), and more jellyfish make their way to the shore.The banana trees are planted in endless monotonous waving rows, right to the edge of the jungle. It takes a full year for these ragged shoots to produce. Once the tree yields its solitary fruit, it dies, and the fecund forest floor becomes barren, the soil degraded. The richness of the rainforest depends on the incessant rhythm of scurrying feet, scrambling mouths, and pulsing decay. When this dance is interrupted, the nutrient cycle stops. It is difficult to start the music back up.

 The Tlapacoyans want to feed their families, which extend voluminously backward and forward in time to include ancestors and grandchildren. Their livestock grazes peacefully between the ancient temples, sacred ball-fields, snaking stone walls and manicured waterways built by the Old People three thousand years ago, in a past that still seems present. And not because they left their plastic bags lying around.

Our task becomes repelling insects, ripening quickly, and packing efficiently, while considering the integrity of the land and maintaining a living for the growers. The bananas must be ready to sell on arrival. The faster the growth-to-market cycle, the more money to be made. Profit, People, Planet, the three 'P's. Especially Profit. It’s time to biologize the question: How does Nature protect, pack, and preserve? We brainstorm a long list of possible organisms and structures, and observe that Nature goes into high gear protecting, preserving, and packing its most precious cargo. Packets of priceless information are horded jealously in genetic vessels of all kinds: eggs and larvae, nests of birds and colony insects, seeds, pods, and cones, even spittlebug foam.

We discard coconuts in favor of honeycomb, a brilliantly lean modular system for protecting larvae, preserving nectar, and packing honey. The hexagon permits no wasted space, and cells and bubbles naturally form hexagons when pressed together. Buckminster Fuller, the genius behind the geodesic dome, knew this. A honeycomb of lightweight, durable, locally available, and ultimately biodegradable bamboo boxes will stack perfectly in the trucks. We can even fold them down for the return trip, using a simple locking rod patterned on the flamingo knee joint. Roberto turns engineer, working the numbers, making blueprints, and constructing a passable model from BBQ skewers and scotch tape.  

Our Champions: the Bonete pod and the multi-storied forest

 

More champions: Sea sponge and spider web

Can we combine this with a peapod duffel-bag structure on the penca to keep out the insects? We walk through the forest, searching for suitable seedpods. We come up with Jacaratia mexicana, the Bonete. This tree grows in the seasonal rainforest, and sports a tough cone-like waterproof ‘berry’, which in cross-section appears as a pentagon. Moisture collects on the exterior and is shunted away to the ground. The berry stays dry until the seeds are ready; the pod breaks free, falls into the moist ground below, and dehisces at huge force, splitting its sides to fire the seeds out for germination. Can we make a bag inspired by the Bonete?

And what about ripening? At home, I tuck unripe fruit in a brown paper bag next to a red apple. The apple emits ethylene, ripening its companion. We find Jose Carlos Cervera, a young Yucateco botany professor who spends his days measuring the exact gaseous inputs and outputs of a couple of individual succulent plants. Grown far too intimate with the secretions of his subjects, Jose hates plants. He’s our man: he tells us about the wide assortment of 'climacteric' fruit that produce ethylene: peppers, pumpkins, bananas, avocados, all locally available. We can grow these alongside the bananas, mimicking the multi-storied forest around us, and simply chuck a few into each box as we pack. But which one? Peppers like to be dry, and avocados are big and shady. Nobody seems enthusiastic about sapote. We settle on pumpkins, grown throughout the year, available in many sizes, and thriving on neglect. In fact, the ancients traditionally planted maize this way, alongside squash and beans, which fix nitrogen into the soil.

Honeycomb and flamingo knees

We need to pull this system of disparate parts together. The sea sponge comes to mind: a porous bag of tissues inside a tough exterior tube. Water draws nutrients through the tube, to be filtered for consumption by the porous bag. Or spider webs, passively filtering insects while the breeze passes through. We can use these strategies to keep insects out, while drawing ethylene in. Our plan emerges: a mesh bag, surrounded by a waxy canvas tube, is tied over the developing penca. The bottom mesh receives ethylene from the pumpkins growing below, while denying entrance to insects. The penca is cut down and separated into bunches. Our hexagonal bamboo structure goes into the bag, and the bananas are packed into it, along with a few small pumpkins. The bag is closed and loaded onto the truck. After unloading, the units are folded down so other items can be brought back to sell in Tlapacoyan. When the grower returns home, he is greeted by the delicious smell of frijoles, platanos, y calabaza. Con mucho gusto, Tlapacoyan!

 

Team Banana: Roberto Ferrer, myself, and Yihad Ghatta