Wombat droppings are cube-shaped.

The Wombat's Remarkable Cube-Shaped Droppings

Of all the bizarre facts the animal kingdom has to offer, the wombat's perfectly cube-shaped droppings rank among the most genuinely astonishing. It sounds like the kind of thing someone makes up to win a pub quiz, but it is entirely real — and the science behind it is surprisingly fascinating.

Why Cubes?

Wombats are native to Australia, and like many animals, they use their droppings to mark territory. But wombats take this a step further by stacking their droppings on rocks, logs, and raised surfaces to make them as visible as possible. A cube, unlike a sphere or a cylinder, doesn't roll away. It sits exactly where it's placed. Evolution, in its quietly brilliant way, gave wombats a built-in solution to a very specific problem.

A typical wombat produces somewhere between 80 and 100 of these little cubes every single night. Each one is roughly two centimetres across. They're left in prominent spots around the wombat's territory as a signal to other wombats — a marker of presence, dominance, and boundaries.

How Does the Body Actually Do It?

This is where things get genuinely interesting. Most cube-shaped objects in nature are formed by external molds or pressure — think crystals or carved stone. The wombat creates its cubes from the inside, purely through the mechanics of its digestive system.

Research published in 2018 by scientists at the Georgia Institute of Technology revealed the secret: it's all in the intestine. A wombat's intestine is not uniformly elastic like a human's. Instead, it has sections of varying stiffness — some parts stretch easily, others barely at all. As waste moves through these alternating sections, it gets shaped into distinct corners and flat faces. By the time it exits, it has been moulded into a near-perfect cube, no external force required.

The team used CT scans and physical models to study the process, eventually identifying two distinct stiff regions in the final stretch of the wombat's intestine responsible for forming the cube's corners. It was the first known example of this kind of intestinal geometry producing a non-cylindrical shape in any animal.

The Ig Nobel Prize

In 2019, this research was awarded an Ig Nobel Prize — the annual awards given for science that "first makes you laugh, then makes you think." The wombat digestion team accepted their prize in physics, because understanding how soft tissue can consistently produce a geometric solid has real-world engineering implications. Researchers have since explored how similar principles might be used in manufacturing to produce soft cubes or square-shaped tubes without the need for rigid molds.

Nature's Unexpected Engineer

The humble wombat, a stocky burrowing marsupial that mostly minds its own business in the Australian bush, turns out to be one of nature's more remarkable engineers. It solved a territorial communication problem and accidentally handed scientists a new way of thinking about shape-making. Not bad for a creature most famous for looking slightly grumpy.