His whole soul was absorbed with worms just at present
From Darwin's notebooks to a modern physics laboratory, the humble coil of animal feces has finally yielded its geometric secrets. Three physicists working across the Netherlands and France have shown that the characteristic shapes of animal droppings—whether falling downward in familiar spirals or extruded upward against gravity by burrowing lugworms—obey the same universal elastic rope-coiling laws that govern cables and ropes. What began as a Victorian naturalist's consuming obsession has become a window into how living organisms unconsciously recruit the laws of physics to serve survival, from preventing burrow collapse to building the fertile soils on which ecosystems rest.
- A century-old mystery posed by Darwin—why lugworm feces coil into uniform-width towers rather than tapered spirals—has finally been cracked by physicists using pea dough, rice noodles, and spaghetti as stand-ins for intestinal matter.
- The tension between the comic and the consequential runs through the entire study: serious researchers publishing rigorous equations about poop geometry are simultaneously revealing how deeply physics is embedded in biological form.
- Lugworms defy gravity when they defecate, pushing waste upward through their burrow entrances at low tide, and that single inversion of direction produces a structurally distinct coil that protects the burrow from tidal collapse.
- The research reframes fecal morphology not as biological trivia but as functional engineering—earthworm castings, governed by these same principles, have been quietly building fertile topsoil for millions of years.
- The physicists now plan to petition the Unicode Consortium for an antigravitational poop emoji, a small but pointed reminder that even the most overlooked phenomena can carry universal significance.
Charles Darwin spent his final years obsessively documenting worm feces, confessing to a friend in 1880 that his whole soul was absorbed with worms. More than a century later, physicists Mehdi Habibi, Neil Ribe, and Daniel Bonn have vindicated that obsession by demonstrating that the shapes of animal droppings follow universal physical laws.
The familiar soft-serve spiral of the poop emoji reflects what happens when an animal defecates downward—a shape governed by intestinal diameter, muscular force, fall distance, and fecal consistency. But this downward pattern tells only half the story. Lugworms, which live in U-shaped burrows beneath tidal sand, do something unusual: they extrude their feces upward against gravity. The result is a coil of uniform width along its entire length, structurally distinct from the tapered point of downward-falling waste—a shape Darwin had noticed but never explained.
To decode the mechanics, the researchers studied fresh lugworm feces alongside analogous materials under controlled conditions, finding that the coil obeys the same elastic rope-coiling theory that governs how cables wind upon themselves. The uniform width is a direct consequence of upward extrusion combined with the material's inherent stiffness, and the resulting structure resists tidal hydraulic forces, keeping the burrow entrance from collapsing.
The implications reach beyond the comic. The study illuminates how organisms unconsciously harness physics to serve survival—and in the case of earthworms, those coiled castings have been building fertile soil for millennia. As Darwin wrote in his final published work, it may be doubted whether any other animals have played so important a role in the history of the world. The three physicists now plan to propose an antigravitational poop emoji to the Unicode Consortium—a fitting tribute to a man who believed even the smallest creatures, and their waste, held secrets worth understanding.
Charles Darwin's name conjures images of finches and evolution, but in his final years, the naturalist became consumed by something far less glamorous: worm poop. He filled notebooks with meticulous observations of how fecal matter coiled into spiraling towers, and in November 1880, he confessed to a friend that his whole soul was absorbed with worms. More than a century later, three physicists—Mehdi Habibi, Neil Ribe, and Daniel Bonn—have vindicated Darwin's obsession by discovering that the shapes of animal feces follow universal physical laws.
The research began with a simple observation: nearly everyone has noticed that animal droppings tend to coil in characteristic ways. The soft-serve spiral of the poop emoji represents the most familiar pattern—what happens when an animal defecates downward. The shape depends on several factors working in concert: the diameter of the intestinal tract, the force of muscular contractions, how far the material falls, and how thick or thin the fecal matter is. Yet this downward-coiling pattern tells only part of the story.
The physicists, based at institutions in the Netherlands and France, focused their attention on lugworms, creatures that live in U-shaped burrows beneath the sand. Unlike most animals, lugworms defy gravity when they poop. At low tide, they position their anus near the burrow entrance and extrude their feces upward onto the beach. This antigravitational defecation produces something the current emoji set does not capture: a coil with uniform width along its entire length, rather than the tapered point of downward-falling feces. Darwin had noticed this distinctive shape decades earlier, but only now has physics explained why it occurs.
To understand the mechanics, Habibi, Ribe, and Bonn examined fresh lugworm feces alongside materials with similar properties—pea dough, rice noodles, and spaghetti—under controlled conditions. They discovered that the lugworm's coil follows the same elastic rope-coiling theory that governs how ropes and cables wind upon themselves. The constant width is simply a consequence of the material being pushed upward rather than falling downward, combined with the inherent stiffness of the fecal matter. The coiled structure serves a practical purpose: it resists the hydraulic forces of tidal inundation and prevents the burrow entrance from clogging or collapsing.
This may sound absurd—and there is something undeniably comic about physicists publishing serious research on poop geometry—but the implications extend beyond the merely amusing. The study reveals how organisms harness physics to shape their bodies and behaviors in functional ways. In the case of earthworms, those coiled castings have literally built the world we inhabit. As Darwin himself wrote in his final published work, devoted entirely to worms, it may be doubted whether any other animals have played so important a role in the history of the world. Their feces, worked into the soil over millennia, created the fertile ground on which ecosystems depend.
The three physicists plan to propose a new emoji to the Unicode Consortium—one that represents antigravitational poop, the shape that Darwin observed but could never have named with a digital symbol. It is a fitting tribute to a man who spent his last years convinced that the smallest creatures deserved the closest attention, and that even their waste products held secrets worth understanding.
Citas Notables
My whole soul is absorbed with worms just at present— Charles Darwin, November 1880
It may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures— Charles Darwin, final published work on worms
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that poop coils follow physical laws? Isn't this just describing something we already see?
Because seeing and understanding are different things. Darwin saw the coils but couldn't explain them. Now we know they're not random—they're governed by the same physics that governs rope-coiling. That tells us something profound about how life uses physics to solve problems.
What's the practical difference between downward-coiling and upward-coiling poop?
Everything, if you're a lugworm. Downward poop tapers because gravity pulls it thin. Upward poop stays uniform because it's being pushed against gravity. That uniform coil is stronger, more stable—it won't collapse the burrow entrance when the tide comes in.
So Darwin was right about the shape, but he didn't know why?
Exactly. He documented it beautifully. But the physics—the elastic rope theory, the role of viscosity and stiffness—that's what took another hundred years to understand. He had the observation. Science had to catch up with the explanation.
Does this research actually help us understand anything beyond poop?
It helps us understand how organisms use physics to build functional structures. The same principles that govern poop coils might apply to how other soft materials move through constrained spaces. And it reminds us that even the smallest, most overlooked processes—earthworm castings—can be foundational to entire ecosystems.
Why propose a new emoji for this?
Because the current emoji only represents one type of poop—the downward kind. If we're going to have a symbol for something so universal, it should acknowledge that nature does it multiple ways. It's a small gesture toward completeness.