Wombat

Cubic poop

The wombat is the only animal known to produce cube-shaped feces. The cubes — typically 2 cm on each side — are deposited in piles of 80–100 on rocks, logs, and prominent surfaces as territorial markers.

For decades the mechanism was unknown. Research published in 2021 identified the cause: the final section of the wombat intestine has two regions of alternating stiffness — stiffer and softer tissue — that create the cubic shape during muscular contractions. This is the only known example of cube formation by soft-tissue squeezing rather than molds.

The cubes are thought to be easier to stack and less likely to roll off elevated surfaces — an advantage for leaving visible territorial marks.

The backward pouch

Wombat pouches open backward — toward the tail rather than toward the head. This prevents soil from filling the pouch while the mother is excavating burrows. The joey develops inside the pouch for about 6–7 months before emerging.

Armored rear end

The wombat’s rump is reinforced with dense cartilage and tough skin. When threatened inside a burrow, a wombat will lower its hindquarters to block the entrance. A predator (dingo, thylacine historically) pushing its head in to investigate gets the rump pressed against the burrow roof — with crushing force. Dingoes have been killed this way.

Conservation

Common wombats (Vombatus ursinus) are abundant. The two hairy-nosed wombat species are both threatened — the Southern Hairy-nosed Wombat (Vulnerable) and the Northern Hairy-nosed Wombat, one of the most endangered large mammals on Earth with under 300 individuals remaining.