Being a part of nature, the animal kingdom has many mysteries. Among them, is the enigma behind wombat excretion – more specifically, why is it shaped like a cube? The animal itself is a marsupial, native to Australia. There has always been much curiosity as to why wombats excrete in this manner however no proper research has been conducted to discover the actual answers. This task was taken on by Patricia Yang, a postdoctoral fellow in mechanical engineering.
Yang herself being very curious about the shape of the excrement wanted to analyze the role played by soft tissue structure and the digestive process of wombats. Initially, she and her team did not have access to any wombat innards. North America did not have any zoos with wombats that could be dissected, so ultimately Yang and her team were shipped the intestines of roadkill from Australia. These specimens were provided by Scott Carver (a member of Yang’s team and a biologist).
As part of the research, Yang and her team used balloons to expand the intestines of the wombat, but also those of a pig. The latter was included for the sake of comparison. The reasoning behind this is that feces are at least in part shaped by intestinal pressure, so it can be concluded that the shape of the intestines will play a role in the shape of the fecal matter.
The results of this experiment illustrated that pig intestines are consistently elastic, as can be observed by their rounder excrement while wombat intestines possess two ravine-like grooves. These sections are also more elastic. As observed by the team the excrement transformed from a liquid state to a more solid and cube-shaped state, concluding that the reason for this was related to intestinal elasticity.
The observations outlined above greatly assist one’s understanding of ‘how’ the fecal matter ends up cube-shaped; though one might still wonder about the ‘why’. Like many other members of the animal kingdom, wombats use excrement to mark territory. Their way of going about this is piling up the feces anywhere that’ll stand out (on logs, burrows, etc.). It becomes a visual and odor-based form of communication between wombats, where a high pile and a strong smell conveys that they are safe and have company. If the excrement was rounder, it would be less likely to stay in place so the cube shape helps guarantee that the pile will remain intact.
Commenting on the study, Yang has expressed that she hopes for continued research into soft tissue transportation and that the findings of this venture are beneficial to both biology and mechanical engineering. She’s also shared that her research is on-going as there are still questions that need to be answered.