Thunder Birds, Australia's Big Ugly Ducklings象鸟，澳大利亚的巨型丑小鸭

The world’s biggest-ever bird weighedas much as a cow and lived in Australia until50，000 years ago.

The flightless Dromornis stirtoni1plodded along on two hind legs. It was thelargest member of an extinct group ofcreatures called the mihirungs—based on anAboriginal word for giant2 bird.

In a new research， scientists describedhow they analysed3 the ancient skulls4 ofmihirungs to get a better idea of their brains.

They discovered that the animals’hugeheads left little room for brains， giving riseto some strangely shaped skulls.

“Together with their large， forward -facing eyes and very large beaks5， the shapeof their brains and nerves suggested thesebirds likely had well-developed depth perception6and fed on a diet of soft leaves andfruit，”said study lead author.

世界上最大的鸟有一头牛那么重，它5 万年前生活在澳大利亚。

不会飞的史氏雷啸鸟用两条后腿缓慢前行。它是一个灭绝的生物群mihirungs（原住民语“巨鸟”的意思）中最大的一个，这个生物群的名字来源于土著人对巨型鸟的称呼。

在一项新研究中，科学家们描述了他们是如何分析巨鸟的远古头骨来更好地了解它们的大脑的。

他们发现，这些动物巨大的头部几乎没有给大脑留下空间，因此产生了一些形状奇特的头骨。

这项研究的主要作者说：“加上它们前视的大眼睛和非常大的喙，它们的大脑和神经的形状表明，这些鸟可能有很好的深度感知能力，并且以柔软的树叶和水果为食。”

“The shape of their brains and nerveshave told us a lot about their sensorycapabilities7， and something about theirpossible lifestyle which enabled theseremarkable8 birds to live in the forestsaround river channels9 and lakes acrossAustralia for a very long time.”

Nicknamed“Thunder Birds”， mihirungs lived across Australia for millions of years.

The largest species Dromornis stirtoni could grow to 3m tall and weigh about 600kg.

The researchers discovered thatmihirung brains and nerves10 were most likethose of modern day chickens andAustralian malleefowl11.

“The unlikely truth is these birds wererelated to chickens and ducks， but theirclosest cousin and much of their biologystill remains a mystery，”said study authorDr. Trevor Worthy.

“它们的大脑和神经的形状告诉了我们很多关于它们的感知能力，以及它们可能的生活方式的一些信息，这种生活方式使这些非凡的鸟类能够在澳大利亚的河流和湖泊周围的森林中生活很长一段时间。”

这些巨鸟被称为“象鸟”，在澳大利亚生活了数百万年。

最大的物种史氏雷啸鸟可以长到3 米高，约600 公斤重。

研究人员发现，巨鸟的大脑和神经与现代鸡和澳大利亚眼斑冢雉最为相似。

研究报告的作者特雷弗·沃西博士说：“难以置信的事实是，这些鸟类与鸡、鸭有亲缘关系，但它们最近的近亲以及它们的大部分生物学特性仍然是一个谜。”

The team used CT scans of the skulls to create casts of the creatures’brains.

The largest and last species Dromornisstirtoni， which died out 50，000 years ago， wasan “extreme evolutionary12 experiment”， DrWorthysaid.

“This bird had the largest skull butbehind the huge bill was a strangecranium13，”he explained.

“To accommodate14 the muscles towield15 this huge bill， the cranium hadbecome taller and wider， and so the brainwithin was squeezed16 and flattened17 to fit.”

研究小组对这些头骨进行了CT 扫描，建立了这些动物的大脑模型。

最大也是最后的物种史氏雷啸鸟在5 万年前就灭绝了，这是一个“极端的进化实验”，沃西博士这么说。

“这只鸟有最大的头骨，但在巨大的喙后面有一个奇怪的头盖骨。”他解释说。

为了容纳肌肉挥舞这张大嘴，它们的头盖骨变得越来越高，越来越宽，因此内部的大脑随之被挤压扁平。”

（英语原文选自：kidsnews.com.au）