Wascally Wombat: Georgia Scientists Solve Its Pooping Mystery

ATLANTA, GA – Scientists have wondered for some time, how do wombats make cubed poo?

A team of scientists, led by the Georgia Institute of Technology's Patricia Yang, say they have unraveled one of the animal kingdom's more interesting mysteries: why wombat poop is cube-shaped. Yang and her team presented their findings about the digestive processes behind the wombat poo mystery at the 71st annual meeting of the American Physical Society's Division of Fluid Dynamics in Atlanta Sunday.

"Wombats are fossorial herbivorous Australian marsupials with the distinctive feature of producing cubic feces, which is unique in the animal kingdom," study authors said in the study's abstract. Because it's a rarity in nature, the poop production was ripe for research, which is where the Georgia team waded into the stinky topic.

"In the built world, cubic structures are created by extrusion or injection molding, but there are few examples of this feat in nature. We investigate how wombats produce cubic feces, through investigation of the structure and mechanics of two dissected alimentary systems of wombats--derived from veterinary euthanized individuals following motor vehicle collisions in Tasmania, Australia," researchers wrote.

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In the final 8 percent of the intestine, feces changed from a liquid-like state into a solid state composed of separated cubes of length 2 cm, scientists found. This shape change was due to the azimuthally varying elastic properties of the intestinal wall, researchers said.

"By emptying the intestine and inflating it with a long balloon, we found that the local strain varies from 20 percent at the cube's corners to 75 percent at its edges. Thus, the intestine stretches preferentially at the walls to facilitate cube formation. This study addresses the long-standing mystery of cubic scat formation and provides insight into new manufacturing techniques for non-axisymmetric structures using soft tissues," authors said in the study's abstract.

Poo comes in many different sizes, from the microscopic poo of the smallest invertebrates, to the largest poo of the African elephants who can each produce over 50kg per day, according to IFLSCIENCE! It also comes in many shapes, such as tubes (dogs), pellets (rabbits) or splats (cows), but the wombat is unique in the animal kingdom in that it produces cubic poo, and lots of it – around 80 to 100 cubes per night.

To solve the riddle, the Georgia team examined the digestive tracts of wombats that had to be euthanized following vehicle collisions in Tasmania, Australia.

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