世界上最危险的鸟是如何长出它独特的羽毛的

世界上最危险的鸟是如何长出它独特的羽毛的

It's been called the world's most dangerous bird. Its long dagger-like toes, in fact, were responsible for the death of a man in Florida last year.

它被称为世界上最危险的鸟。事实上，它那像匕首一样的长脚趾导致了去年佛罗里达州一名男子的死亡。

But what excites scientists about the cassowary — a large, emu-like, flightless bird — is its distinctive look. With its black iridescent feathered body, its blue, turquoise and magenta neck and horned crest, it's been described as looking like a "high-fashion dinosaur."

但是，让科学家们兴奋的是，这种大型的、类似鸸鹋的、不会飞的食火鸟有着与众不同的外表。它有着黑色夹着彩虹色的羽毛身体，蓝色、蓝绿色和洋红色的脖子，以及有角的羽冠，被形容为“高级时尚恐龙”。

"It's a little over a meter tall. It's pretty heavy. Their bones are dense. They definitely can cause some damage," said Chad Eliason, a staff scientist and postdoctoral fellow at the Field Museum in Chicago and an author of a new paper on the giant bird that published Wednesday in the journal Science Advances.

“它有一米多一点高。它很重。它们的骨骼很致密。它们肯定会造成一些损害，”查德·埃利亚松说。他是芝加哥菲尔德博物馆的研究员和博士后，周三在《科学进展》杂志上发表了一篇关于这种巨型鸟类的新论文。

"There's lots of stories about dangerous kicks with their claws. They help you to realize birds are related to dinosaurs."

“有很多关于用危险的爪子踢人的故事。它们帮助你认识到鸟类和恐龙是有联系的。”

Each of its three-toed feet has a claw that can be up to 4 inches or 10 centimeters long, allowing it to slice open a predator with a single kick, according to the San Diego Zoo. It can also run up to 31 miles per hour through dense forest and jump up to 7 feet (2 meters).

根据圣地亚哥动物园的说法，它的三趾脚各有一个长达4英寸或10厘米的爪子，可以一脚踢开捕食者。它还可以在茂密的森林中以每小时31英里的速度奔跑，跳跃高度可达7英尺(2米)。

High gloss

高光泽

New research on the feathers taken from a dead bird has now revealed what gives cassowary feathers their glossy black shine.

对取自一只死鸟的羽毛的最新研究现在已经揭示了是什么使食火鸡的羽毛呈现出光滑的黑色光泽。

"Understanding basic attributes — like how colors are generated — is something we often take for granted in living animals," said paleontologist Julia Clarke, a professor at the Jackson School of Geosciences at the University of Texas at Austin and the paper's senior author.

德克萨斯大学奥斯汀分校杰克逊地球科学学院教授、该论文的资深作者、古生物学家朱莉娅·克拉克说:“了解基本属性——比如颜色是如何产生的——是我们通常认为了解活的动物应该具备的(知识)。”

"Surely, we think, we must know everything there is to know? But here, we started with simple curiosity. What makes cassowaries so shiny?"

“当然，我们认为，我们必须知道所有该知道的事情吗?但在这里，我们从简单的好奇心开始。是什么让食火鸡如此闪亮?”

Unlike in other shiny birds, such as hummingbirds or crows, the cassowary's glossiness is produced by the rachis, or the spine of the feather, rather than the barbules, or minute filaments fringing a feather.

与其他有光泽的鸟类，如蜂鸟或乌鸦不同，食火鸡的光泽是由羽轴或羽毛的脊柱产生的，而不是由羽枝或羽毛边缘的细丝产生的。

Since the fluffy barbules on cassowary feathers are pretty sparse, the rachis gets more exposure to light than in "thick-feathered" birds, giving it a chance to literally shine.

由于食火鸡羽毛上蓬松的羽枝相当稀疏，因此与“厚羽毛”鸟类相比，羽轴能接触到更多的光线，这就给了它真正闪亮的机会。

"The gloss is in a totally different part (compared to other birds). You picture a feather being like a tree, the gloss is in the trunk of the tree, not the branches," Eliason explained.

“与其他鸟类相比，这种光泽是完全不同的。你想象一根羽毛就像一棵树，光泽在树干上，而不是树枝上，” 埃利亚松解释说。

The study suggested that the cassowary's unique gloss-producing mechanism would have evolved gradually over time, with an ancestral bird losing its barbules and the cassowary developing a thicker central feather shaft.

这项研究表明，食火鸡独特的产生光泽的机制会随着时间的推移逐渐进化，一只祖传的鸟失去了它的羽枝，而食火鸡进化出了更厚的中央羽毛轴。

Eliason suspected that flightlessness might have given cassowaries more evolutionary room to develop their odd-shaped feathers.

埃利亚松怀疑，没有飞行能力可能给了食火鸡更多的进化空间来发展它们的奇形怪状的羽毛。

"Losing that constraint, that need to fly, might result in new feather morphologies that produce gloss in a way that a flying bird might not."

“失去这种约束，即需要飞翔的约束，可能会导致新的羽毛形态，以一种飞行的鸟类可能不会的方式产生光泽。”