Rubik’s Poops

Pooping bricks — it’s just an expression! Or is it…?!

This is Sandra Tsing Loh with the Loh Down on Science.

Everybody poops, but only one animal poops CUBES. The wombat, a chubby little marsupial from Australia, drops DICE-shaped doo-doos! Neat trick – but how?

David Hu and team at Georgia Institute of Technology stuck their noses into this mystery.

Wombats’ — er, “openings” aren’t square. So, the next place they looked? The GUTS. It turns out, wombat intestines are unique. They have an “O” cross section with alternating stiff and loose parts. Other mammals’ intestines have the same stiffness all around. Wombats? More like an uneven rubber band!

But does THAT explain the wombats’ pixelated waste? To find out, the team went digital. They used a computer program to simulate an intestine cross section squeezing. 

Results? The inner shape molded into a square! Wombats’ unevenly stretchy guts produce sharp corners where the poop gets pinched together. Play-Doh skills, right?

Now we know how this animal NATURALLY makes UNNATURAL shapes. 

Talk about a square deal!

Reference: Yang, P., Lee, A., Chan, M., Kowalski, M., Qiu, K., Waid, C., Cervantes, G., Magondu, B., Biagioni, M., Vogelnest, L., Martin, A., Edwards, A., Carver, S., & Hu, D. Intestines of non-uniform stiffness mold the corners of wombat feces. Soft Matter 17, 475 (2019).