Wombat poop is cube-shaped due to the unique anatomy and digestive processes of these marsupials. Unlike most mammals, wombats have a highly specialized rectum with muscular rings that form distinct compartments. These compartments allow the wombat to control the shape of its feces by exerting pressure from different angles, essentially molding the feces into a more solid form.

The cubic shape of wombat scat is advantageous for wombats in several ways:

1. Territory Marking: Wombats deposit their droppings on raised platforms, rocks, or logs, and the cubic shape prevents them from rolling away, ensuring their scent markers remain in place for territorial communication.
2. Adaptation to Habitat: The ability to create firm, stackable feces may also be an adaptation to the rocky environments in which wombats live, as round droppings might roll off cliffs or ledges, whereas cubes are more likely to stay put.

The distinctive cube shape of wombat poo remains a fascinating biological curiosity and has inspired scientists to study the physics and mechanics behind this natural phenomenon.