终于！科学家研究出了为什么袋熊的便便是方的！

The wombat, native to Australia, produces about 80 to 100 cubes of poop each night. It is known to deposit piles of dung outside burrows and on top of rocks and logs, most likely to communicate with other wombats, researchers believe.

袋熊原产于澳大利亚，每晚产生大约80到100块粪便。它们会在洞穴外、岩石和原木上堆积大量粪便，研究人员认为这种行为很有可能是在与其他袋熊交流。

"Wombats have really strong sense of smell that they use probably for communication," said University of Tasmania wildlife ecologist Scott Carver, who co-authored the study. "We don't know what that information they're sharing is, but it might be something about mating, it might be something about general advertising about who's in the area."

“袋熊的嗅觉非常强大，可能是用来互相交流的，”塔斯马尼亚大学野生动物生态学家Scott Carver说，他是这项研究报告的著者之一。“我们不知道它们分享的信息是什么，但可能是关于交配的，也可能只是关于谁在这一区域的告知。” 

It is thought that the cubed shape of the poop means it is less likely that it will roll away, and is prominent for other individuals to notice and smell, Carver added.

Carver补充说，研究人员认为，立方形状的粪便意味着不太容易滚走，而且更容易被其他袋熊看到和闻到。

But how the wombat produces the cubed shapes is a phenomenon that has puzzled many observers of the furry marsupial.

但是袋熊是如何产生立方体形状的粪便的呢？这一问题困扰着许多观察这种毛茸茸的有袋类动物的人。

Researchers, led by the Georgia Institute of Technology's Patricia Yang, said they have uncovered the digestive processes behind the mystery and presented their findings at the 71st Annual Meeting of the American Physical Society's Division of Fluid Dynamics in Atlanta on Sunday. 

由乔治亚理工学院的帕特里夏·杨(Patricia Yang)领导的研究人员表示，他们已经发现了这一谜团背后的消化过程，并于周日在亚特兰大举行的美国物理学会流体动力学分会第71届年会上公布了他们的研究成果。

The wombat's cubed faeces is a trait that's unique in the animal world, the researchers said, as cubes are usually created by cutting or molding.

研究人员说，袋熊的立方体形状的粪便是动物世界中独一无二的，因为立方体通常是通过切割或用模子制作而成的。

"In the built world, cubic structures are created by extrusion or injection molding, but there are few examples of this feat in nature," authors of the project said in the study's abstract.

 “在建筑学领域，立方体结构是通过挤压或注塑而成的，但在自然界中很少有这样的例子，”该项目的作者在研究摘要中说。

To solve the puzzle, the team examined the digestive tracts of wombats that had to be euthanized following vehicle collisions in Tasmania, Australia.

为了解开这个谜题，研究小组检查了在澳大利亚塔斯马尼亚遭遇车祸后即将被安乐死的一只袋熊的消化道。

The wombat takes about two weeks to digest its food and researchers found that as faeces move into the final 8% of the intestine, it changes from a liquid-like state into solid matter. At that stage the dung takes on the shape of separated cubes measuring about two centimeters in length.

袋熊花费约两周的时间消化食物，研究人员发现，随着粪便移入最后8%的肠，粪便会从类液体态变成固态。这个阶段，粪便呈现出约两厘米长的立方体的形状。

"The weird thing is that if you open up a wombat you actually find that the cubes become formed in the lower part of the intestine, before they exit the body," Carver said.

“奇怪的是，如果你打开一只袋熊，你会发现立方体是在离开身体前，在肠的末端形成的。” Carver说。

By inflating the intestine with a long balloon, the researchers found that the wombats' intestine walls stretch unevenly, allowing for the formation of the cube shapes.

研究人员用长气球给袋熊的肠充气后发现，袋熊的肠壁会不均匀伸缩，从而使粪便形成立方体的形状。

"The local strain varies from 20% at the cube's corners to 75% at its edges," the team said.

研究小组表示：“ 造成袋熊粪便立方体的压力是不同的，角上的压力有20%，棱上有75%。”

"Basically around the circumference [of the intestine], there are some parts that are more stretchy and some parts that are more stiff," Carver said. "And that is what creates the edges and the cubing."

“基本上，（肠道）有的地方更有弹性一点，有的地方更紧实一点，”Carver说，“立方体和棱角正是通过这样的构造产生的。”

The study's authors said the findings could have implications beyond the natural world, by helping to provide insight into new manufacturing techniques.

该研究作者表示这项发现不止暗示着自然信息，可能会为新生产技术提供视角。

"There is a long history of people looking to the natural world for innovations in human society," Carver said. "This potentially reveals another mechanism of producing cubed-shaped objects and in that sense it could contribute to thinking about manufacturing these sorts of objects in different ways."

“人类很早就开始从自然界得到启示而在人类社会开展革新，”Carver说，“这项发现可能揭示了另一种生产方形物品的机制，并且从这种意义上来讲，它还能为生产此类物品提供不同的思路。”