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How, and why, do wombats make cube-shaped poo?


Yang, P and Lee, A and Chan, M and Martin, A and Edwards, A and Carver, S and Hu, D, How, and why, do wombats make cube-shaped poo?, IgNobel Prize for Physics, Improbable Research, United States (2019) [Award]

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Wombats are fossorial herbivorous Australian marsupials with the distinctive feature of producing cubic feces, which is unique in the animal kingdom. 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. 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. This shape change was due to the azimuthally varying elastic properties of the intestinal wall. 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.

Cited work: How do wombats make cubed poo?

Item Details

Item Type:Award
Research Division:Engineering
Research Group:Fluid mechanics and thermal engineering
Research Field:Microfluidics and nanofluidics
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Martin, A (Ms Alynn Martin)
UTAS Author:Edwards, A (Dr Ashley Edwards)
UTAS Author:Carver, S (Dr Scott Carver)
ID Code:134955
Year Published:2019
Deposited By:Zoology
Deposited On:2019-09-16
Last Modified:2019-09-16
Downloads:28 View Download Statistics

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