袋鼠、熊猫，会有什么关系呢？
冰河时代的大袋鼠与大熊猫有着独特的联系
More than 40,000 years ago, the landscape of southwestern Australia was replete with giant kangaroos.
4万多年前，澳大利亚西南部的风景里满是巨型袋鼠。
One of these extinct kangaroos, known as a short-faced kangaroo, boasted a single-toed clawed foot (modern-day roos have three toes), weighed more than 260 pounds (118 kilograms), and munched on plants.
其中一种已经灭绝的袋鼠，被称为短面袋鼠，拥有单趾爪足(现代袋鼠有三个脚趾)，体重超过260磅(118公斤)，以植物为食。
According to a new study published in the journal PLOS One, these creatures' large jaws allowed them to chomp through tough foods like mature leaves, stems, and branches when other food sources were scarce.
根据发表在《公共科学图书馆·综合》(PLOS One)杂志上的一项新研究，当其他食物来源匮乏时，这些生物的大下巴可以让它们咀嚼成熟的叶子、茎和树枝等坚硬的食物。
(N. Tamura)
Only one animal today has similar jaw bones and muscles: giant pandas, which also eat hard-to-chew, thick vegetation like bamboo shoots.
如今只有一种动物有类似的颌骨和肌肉:大熊猫，它们也吃难以咀嚼的厚植被，如竹笋。
In fact, the new research indicates, the kangaroo's jaw was more similar in shape and function to that of today's giant pandas than to modern-day kangaroos.
事实上，这项新的研究表明，袋鼠的下巴在形状和功能上更像今天的大熊猫，而不是现代的袋鼠。
Scientists already guessed that these giant kangaroos' jaws enabled them to consume hard-to-chew vegetation. Mitchell decided to test that theory by determining how much force the skull could resist.
科学家们已经猜测，这些巨型袋鼠的下颚使它们能够吃掉难以咀嚼的植物。米切尔决定通过确定头骨能抵抗多少力来检验这个理论。
(Wang He/Getty Images)
So he created 3D digital models of a short-faced kangaroo skull and simulated the mechanical forces at play. Mitchell found that the giant cheekbones of this ancient animal supported large muscles that would have prevented the animal's jaw from dislocating during giant bites.
因此，他创建了一个短脸袋鼠头骨的三维数字模型，并模拟了游戏中的机械力。米切尔发现，这种古老动物的巨大颧骨支撑着巨大的肌肉，在巨大的咬合过程中可以防止动物的下巴脱臼。
The bones on the front and top of its skull formed an arch that helped keep the muscles from twisting.
它头骨前部和顶部的骨头形成一个拱形，有助于防止肌肉扭曲。
According to the study, the extinct kangaroo's physiology suggests that it had adapted to take advantage of foods that were difficult to chew more than any Australian herbivore alive today. Modern-day kangaroos, by contrast, prefer grasses, flowers, ferns, and moss.
根据这项研究，这只已经灭绝的袋鼠的生理学表明，它已经适应了利用那些比现在活着的澳大利亚草食动物更难咀嚼的食物。相比之下，现代袋鼠更喜欢草、花、蕨类植物和苔藓。
