Wombats Have Cube-Shaped Poop – Scientists Now Know Why

  • Truly, it is a miracle what science can find out.

As you no doubt know, poop comes in all shapes and sizes. Without going into the filthy details, it’s easy to identify animals by their droppings, and you could probably even tell some people apart from their leavings.

But among all the strangely shaped poops in the world, one must inevitably stand above the rest. We’re handing the Oddee Strangest Crap Award to bare-nosed wombats who poop in cubes.


Really, if you ignore the fact that it’s poop, the wombat droppings are kind of cute. They’re nicely compressed little cubic pellets that you could probably stack pretty neatly, if you were so inclined.

But there’s one question that has plagued scientists and others who like playing with animal feces. Why and how do wombats produce their peculiarly shaped droppings?

Well, worry not, poop lovers. A new study, published in the aptly named journal Soft Matter, finally has conclusive answers that aren’t based on guesswork.

“There were wonderfully colorful hypotheses around, but no one had tested it,” Scott Carver, a wildlife ecologist from the University of Tasmania and one of the study’s authors, told The Guardian.

Some scientists theorized that wombats had a square-shaped butthole. Others posited that wombat poop was squished into shape between the animal’s pelvic bones.

And then there was the idea that wombats shape their poop into cubes after excreting it.

Somehow, we’re glad that last theory didn’t turn out to be real.

Picture of wombat poop courtesy of Bjørn Christian Tørrissen, used under CC BY-SA 3.0 license.

Flexing Some Muscles

It turns out that cubes are formed much higher up in the wombat intestine than anyone previously thought possible. Inside the wombat gut, the intestine has layers of muscle of varying thicknesses that shape the poop into cubes as it passes.

The inspiration for the wombat crap study came from a dead wombat some four years ago. At the time, Carver was carving up a euthanized wombat when he discovered cube-shaped poop pellets in the last yard of the animal’s intestine.

To a scientist that was what Carver described as an “odd moment”.

“How do you produce cubes inside essentially a soft tube?” he asked himself.

And so began the scientific method. Carver teamed up with likeminded researchers and together they set to work.

One part of the team began testing the tensile strength of wombat guts. Meanwhile, physicists in the U.S.-based Georgia Institute of Technology drafted a mathematical model that simulates the creation of the poop cubes.

That’s a lot of high science to put into poop. But the researchers’ efforts yielded results.

They discovered that the thickness of the muscles in the wombat intestine varies between two stiff and two flexible layers. Initially, they thought there were four layers, but no, there are only two.

Somehow, that is significant.

“The rhythmical contractions [of the muscle layers] help form the sharp corners of the cubes,” explained Carver.

This theory was confirmed when Australian researchers performed a CT scan on a live wombat. They found that the muscles, together with the poop drying up in the colon, created the cubic crap.

The Applications of Poop

So now we know how the cubes form inside the wombat. But did the scientist figure out why?

Well, they kind of did. They don’t have bulletproof answers, but according to Carver they have a good theory.

Wombats have a keen sense of smell, and Carver theorized that they could be using their feces to communicate with each other over distances. Cubic poop would be beneficial since it doesn’t roll away like regular round pellets.

And yes, the scientists tested that out. The cube-shaped poop was far less likely to roll away when dropped onto an eight-degree slope than round poop.

“This was one of the more unusual research projects Taronga Zoo has been involved in, a bit quirky, but it does answer a very significant question, one that a lot of people ask,” said Larry Vogelnest, head veterinarian at Taronga Zoo. The CT scanned wombat came from Taronga.

The research could help environmentalists and zookeepers monitor wombat health. David Hu, another author of the study, said that captive wombats sometimes produce rounder feces than wild ones – meaning that they might have less healthy guts.

But there are also implications for human health, believe it or not. The study could help us build machinery that produces cube-shaped objects inside a soft tube.

“These results may have applications in manufacturing, clinical pathology and digestive health,” the study reads.

Maybe one day you can thank a pooping wombat for your consumer goods.

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