But now, thanks to dedicated investigation by a mechanical engineer, the answer could inform a new manufacturing process.
Led by Patricia Yang, a postdoctoral fellow in mechanical engineering who studies hydrodynamics within the bodies of animals at the Georgia Institute of Technology in the US, the research group looked at how the chubby, short-legged marsupial’s digestive processes and soft tissue structures create the regularly shaped stools.
“The first thing that drove me to this is that I have never seen anything this weird in biology. That was a mystery,” said Yang. “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 sceptical.”
Yang and her co-authors studied the digestive tracts of wombats that had been euthanised following motor vehicle collisions in Tasmania, Australia. Near the end of the intestine, they found that faeces changed from liquid-like states to solid states made up of small, separated cubes. The group concluded that the varying elastic properties of wombats’ intestinal walls allowed for the cube formation.
In the built world, cubic structures are common, produced by injection moulding or extrusion. Cubes, however, are rare in the natural world. Wombats are the only known species capable of producing them organically, using the regular shapes to prevent the stools rolling away from piles built for communication.
“We currently have only two methods to manufacture cubes: we mould it, or we cut it. Now we have this third method,” Yang said. “It would be a cool method to apply to the manufacturing process – how to make a cube with soft tissue instead of just moulding it.”
She added: “We can learn from wombats and hopefully apply this novel method to our manufacturing process. We can understand how to move this stuff in a very efficient way.”
Biologist and co-author Scott Carver said: “There is much general interest from the public, both in Australia and internationally, about how and why wombats create cube-shaped faeces. Many ideas, some more entertaining than others, have been put forward to explain this, but until this study nobody had ever investigated the cause. This has been a fantastic collaboration which shows the value of interdisciplinary research for making new scientific discoveries.”
The team will present their findings at the American Physical Society’s Division of Fluid Dynamics 71st Annual Meeting, which is taking place until tomorrow at the Georgia World Congress Centre in Atlanta, Georgia.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.