Scientists have explained a surprising reason behind the cube-like shape of wombat feces. A widely cited explanation comes from research discussed on ABC News, where experts describe the physical forces at work inside the wombat’s digestive system.
Scott Carver and his team have studied wombat droppings for years. Their first notable work appeared in 2018, and the researchers received the Ig Nobel Prize for a finding that combined curiosity with a touch of whimsy. In 2021, the investigators expanded their inquiry and linked the unusual geometry to uneven tissue thickness along the intestines. More recent work has explored why the feces tend to be so consistently shaped and sized across samples.
In earlier studies the team mapped how the sharp corners of the square-like pellet arise in cross section. They noted that while the edges are clearly defined, the pattern of disintegration and the uniformity of blocks remained unexplained at that time, leaving room for new hypotheses about the drying process and internal structure.
To test ideas about how a solid like this could form, the researchers looked to volcanic science. The problem of lava cooling into repetitive, honeycomb-like patterns provided a useful analogy. The idea is that a similar kind of solidification could occur as the wombat feces dry. The comparison suggests that drying dynamics influence how the material cracks and separates into distinct, cubic segments.
For experiments, the team built a dry paste model using cornstarch, a simple plastic conduit to mimic the intestines, and infrared heating to simulate heat flow. They prepared a starch slurry in plastic channels of different sizes and watched what happened as the material dried. The outcome showed that stronger drying prompts smaller and harder fragments, aligning with the observed rigidity and segmentation of real wombat pellets.
To verify the concept, the researchers surveyed existing literature on moisture and crack formation. They reported that cracking tends to begin when water content in the material drops below a threshold and the structure holds together in compact, rounded blocks. In wombat feces, the moisture content is unusually low, with estimates placing water content around 65 percent. This level supports ongoing formation of discrete, compact units as the material dries, helping explain why the stools emerge as cube-like shapes and remain consistently sized when released from the body.
These findings help illuminate a curious intersection between biology and physics. The cube-like shapes are not a random quirk but a consequence of how stress distributes within a drying, fibrous matrix. The result is a stable pattern that persists from the interior of the intestine to the point of extrusion. The research underscores how natural systems exploit basic physical principles to produce dependable outcomes, even in something as everyday as waste.
In summary, the cube-shaped wombat droppings arise from a combination of tissue thickness variation, moisture levels, and controlled drying. The process creates predictable cracks and segments that culminate in compact, roughly cubic pellets. What began as a quirky observation has evolved into a study that links anatomy, materials science, and the physics of drying, offering insights that reach beyond Australian marsupials to broader questions about how living organisms shape their waste through internal structure and environmental conditions. This work continues to stir interest among scientists and the public alike, inviting closer look at the surprising ways nature uses simple mechanics to produce recognizable forms. Attribution: reporting from ABC News and related scientific summaries.