Why do wombats poop cubes?

Wombats leave cube-shaped droppings because their intestines shape them. Researchers from Georgia Tech and the University of Tasmania found that sections of the intestine wall are stiffer than others, and as the wall contracts it presses drying poop into flat sides and corners.

What's actually true

Wombats produce cube-shaped poop, shaped inside their intestines. Wombats are the only animals known to leave cube-shaped droppings. Researchers from Georgia Tech and the University of Tasmania found the shaping happens in the gut, not at the exit. Sections of the intestine wall are stiffer than others, and as the wall contracts, it presses the drying poop into flat sides and corners.

Takeaway: A soft, round tube can still make cubes if its walls stretch unevenly.

Why people believe it

Most people assume a cube must be formed at the exit, the way a nozzle shapes toothpaste, so it sounds like a joke or an internet hoax. The flat sides also make a neat story about droppings that don't roll away, which adds to the feeling it must be a deliberate trick. In fact the shaping itself happens deep in the gut, where uneven stiffness in a soft tube gradually makes corners.

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