Yes, cubes. Nature has apparently found a way to manufacture building blocks from grass.
Researchers investigating bare-nosed wombats discovered that the corners form inside the intestine.
Differences in the stiffness of the intestinal walls, combined with muscular contractions, help shape the droppings before they emerge. The wombat does not have a square exit. That question has been checked.
Female wombats have another practical feature: a backwards-facing pouch. For an enthusiastic excavator, this likely helps keep soil out of the baby’s accommodation.
But the fossil family album is where things get wonderfully oversized.
WHEN THE RELATIVES WERE ENORMOUS
During Australia’s Pleistocene, Diprotodon optatum wandered through landscapes shared with giant kangaroos and marsupial predators. The largest known marsupial, it could weigh around 2.7 tonnes and approach four metres in length.
Often nicknamed a “giant wombat”, Diprotodon belonged to a separate, extinct family. Wombats are among its closest living relatives, but it was a cousin on another branch of the family tree—not an oversized ancestor that eventually shrank into today’s burrow-dweller.
There were genuine giant wombats, too. Phascolonus gigas belonged to the wombat family and had powerful limbs and enormous, strap-like incisors. Its skull had a distinctive dish-shaped top, which researchers have suggested may have supported a protective pad used during head-butting contests. Prehistoric disagreements may have been quite a spectacle.
Living wombats give us a small, sturdy connection to that lost diversity of Australian marsupials. Their fossil relatives remind us that familiar animals can belong to family trees with some surprisingly large branches.
Whether those ancient giants also produced cubes is a question we should leave open.
A family resemblance only tells us so much.
Sources and Further Reading
- Intestines of non-uniform stiffness mold the corners of wombat feces — Soft Matter (2021).
- Ten things you need to know about wombats — CSIRO.
- Diprotodon optatum — Australian Museum.
- Prehistoric Australia — Australian Museum.
