23-3 Sat Jan 2 How the vombatus ursinus forms cubic feces, with an application to the feces of terrestrial mammals Magondu, B*; Cervantes, G; Lee, A; Kaminski, C; Yang, P; Carver, S; Hu, D; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; University of Tasmania; Georgia Institute of Technology bmagondu3@gatech.edu
The Vombatus Ursinus, or the common wombat is known for its cubic feces with six flat faces. In previous work, we showed that wombats form square cross-sections due to the non-uniform material properties of their intestine. In this study, we focus on the remaining two faces of the cube. We mimic wombat feces formation by performing experiments with drying cornstarch slurry in one-dimensional troughs. Cracks naturally form perpendicular to the walls, and with a crack spacing proportional to the trough width. We present a numerical model of this phenomenon, accounting for the diffusion of water through the porous corn starch, which generates dry regions and initiating cracks. We apply our rationale to predicting the size of fecal matter in terrestrial animals, such as rats, gerbils, rabbits, and goats, as a function of moisture content.
