Wombat poop: Scientists reveal mystery behind cube-shaped excrement

Scientists say they have discovered how and why wombats produce cube-shaped poo – the only known species to do so.

The Australian marsupial can spend up to 100 poop deposits per night and uses the batteries to mark the territory. The shape helps to stop rolling.

Although they have round anuses like other mammals, wombats do not produce round pellets, tubular turns, or messy piles.

Researchers revealed Sunday that the varied elasticity of the intestines helped to carve the poop into cubes.

"The first thing that led me to this is that I've never seen anything so strange in biology." It was a mystery, "said Patricia Yang, of Georgia Institute of Technology.

After studying the digestive tract of wombats posed after road accidents in Tasmania, a team led by Dr. Yang presented his findings at the annual meeting of the division of the American physics company, Fluid Dynamics, in Atlanta.

"We opened these intestines as if it were Christmas," said co-author David Hu, also of Georgia Tech, according to Science News.

The team compared the wombat bowel with the pig bowel by inserting a balloon into the animal's digestive tract to check for stretching.

In the wombats, faeces passed from a liquid state to a solid state in the last 25% of the intestines – but then in the final 8%, a varied elasticity of the walls meant that the dung took shape into separate cubes.

Scientists say this resulted in cube-shaped 2 cm (0.8 in) poop, unique to the wombat and the natural world.

The marsupial then stacks the cubes – the higher is the best for communicating with other wombats and attracting them.

"We currently have only two methods to make cubes: we mold them or we cut them in. We now have this third method," said Dr. Yang.

"It would be an interesting method to apply to the manufacturing process," she suggested, "how to create a cube with soft tissue instead of just molding it."