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A walk in the Australian bush can occasionally reveal piles of strange, cube-shaped poo, carefully balanced on top of rocks. Although it might seem like a prank, they’re perfectly natural. Chances are, this cube poo has been ejected from a wombat’s rear end.

Wombats communicate by piling poo in noticeable locations, such as on rocks and logs. Scientists think the poo is cubic so it doesn’t roll off. But there’s one question that scientists are only just starting to get to grips with – how do they make this shape?

In the world of digestion, cubic poo is very strange. Dr Patricia Yang, from the Georgia Institute of Technology in the United States, wasn’t sure if it was even real. “I have never seen anything this weird in biology,” said Patricia. “I didn’t even believe it was true at the beginning. I Googled it and saw a lot about cube-shaped wombat poop, but I was skeptical.”

To find out more, Patricia and her team turned to an Australian researcher, Dr Scott Carver from the University of Tasmania. Scott received two wombats that had been killed, sadly, in car accidents. He sent specimens from these wombats to the United States.

Patricia’s team looked at the contents of the wombat intestines, which were mostly liquid-like. It was only in the last eight percent of the intestine that the poo started to solidify and turn into cubes.

The researchers also tested the properties of the wombat intestines. After emptying the intestines, they filled them with long, thin balloons. The pressure of the balloons revealed some parts of the intestines were much stretchier than others. The differences in stretchiness at key points in the intestines lined up with where the poo cubes were formed.

This is a newly discovered technique for creating a very useful shape. “We can learn from wombats and hopefully apply this novel method to our manufacturing process,” says Patricia. “We can understand how to move this stuff in a very efficient way.”

Want to learn to identify animal droppings? Pick up a copy of our ‘Weirdest wildlife’ issue of Double Helix magazine from the CSIRO Publishing website.