Scientist figures out how wombats poop cubes

The Australian marsupials are the only known animals in the world that produce cube-shaped feces.

Patricia Yang from the Georgia Institute of Technology studied the intestines of roadkill wombats

Wombats are the only animal known to produce feces in the form of cubes with rounded edges. (Felicia Eccles/Taronga Zoo via Getty Images, National Poo Museum/Twitter )
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When Patricia Yang first saw a picture of wombat feces, she thought it was fake.

The Australian marsupials are the only known animals in the world that produce cube-shaped poop.

"I studied feces for two or three years and I know most of the categories," Yang, a Georgia Institute of Technology mechanical engineer who specializes in bodily fluids, told As It Happens host Carol Off. 

"We have watery feces, cylindrical feces like humans normally do, and pellets ... from some small animals and rodents. Wombats [are] really, really unique."

So she did what any curious scientist would do next — she Googled for answers.

Patricia Yang is a researcher at the Georgia Institute of Technology who specializes in bodily fluids. (Submitted by Patricia Yang)

She learned that some biologists theorize wombats use feces to mark their territory, and the square shape makes the poop less likely to roll away.

What's more, the dry climate helps the feces maintain its edges. 

But Yang said there was a dearth of information about how their bodies actually produce feces in a shape rarely seen in nature. 

Roadkill intestines 

"I was skeptical about all the resources I could find online, so I decided I need something real," she said. "So I reached out to a wombat expert in Tasmania."

He sent her some feces-filled wombat intestines from his personal collection of frozen roadkill specimens, and she and her colleagues set about learning how they worked.

Wombats have intestines that are both elastic and rigid. (Rolf Vennenbernd/AFP/Getty Images)

They stretched the intestines out with a balloon to study their elasticity, and did the same with pig intestines for comparison.

While the pig intestines had uniform elasticity, the wombat ones had "periodic stiffness," she said — or hardened grooves that help transform the feces into its cubical shape.

As the feces moves through the intestines, Yang said, it starts to form into more evenly shaped chunks with sharper edges.

The findings were presented at the American Physical Society Division of Fluid Dynamics' annual meeting in Atlanta.

Yang said she believes the study could have implications for manufacturing, where cube shapes are usually achieved through molding or carving. 

"This method could inspire us about what's an easier way or a cheaper way and portable way to make [cubes]," she said.

"We are learning from wombats."

Written by Sheena Goodyear. Produced by Kate Swoger.

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