Unique physiology allows the Australian marsupial to produce square-shaped faeces that may aid communication

How wombats produce their cube-shape poo has long been a biological puzzle but now an international study has provided the answer to this unusual natural phenomenon.

The cube shape is formed within the intestines – not at the point of exit, as previously thought – according to research published in scientific journal Soft Matter on Thursday.

The paper expands upon preliminary findings first presented at a meeting of the American Physical Society’s fluid dynamics division in Georgia in 2018.

Dr Scott Carver, wildlife ecologist at the University of Tasmania and one of the authors of the research paper, said “there were wonderfully colourful hypotheses around but no one had tested it”.

There was speculation that wombats had a square-shaped anal sphincter, that the faeces get squeezed between the pelvic bones, as well as the “complete nonsense” idea that wombats pat the faeces into shape after they deposit them.

The project originated four years ago when Carver was dissecting a euthanised wombat hit by a car and noticed the cubes in the last metre of the wombat’s intestine. Carver described it as an “isn’t that odd moment”.

“The thing that is striking, how do you produce cubes inside essentially a soft tube?”

The team of researchers in Australia, including the head veterinarian at Taronga zoo, Larry Vogelnest, tested the tensile strings of the intestine while physicists in the US based at the Georgia Institute of Technology created mathematical models to simulate the production of cubes.

The team discovered big changes in the thickness of muscles inside the intestine, varying between two stiffer regions and two more flexible regions.[…]

Read more: Box seat: scientists solve the mystery of why wombats have cube-shaped poo