袋鼠、熊貓，會有什么關(guān)系呢？

冰河時代的大袋鼠與大熊貓有著獨特的聯(lián)系

More than 40,000 years ago, the landscape of southwestern Australia was replete with giant kangaroos.

4萬多年前，澳大利亞西南部的風景里滿是巨型袋鼠。

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.

其中一種已經(jīng)滅絕的袋鼠，被稱為短面袋鼠，擁有單趾爪足(現(xiàn)代袋鼠有三個腳趾)，體重超過260磅(118公斤)，以植物為食。

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.

根據(jù)發(fā)表在《公共科學圖書館·綜合》(PLOS One)雜志上的一項新研究，當其他食物來源匱乏時，這些生物的大下巴可以讓它們咀嚼成熟的葉子、莖和樹枝等堅硬的食物。

(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.

如今只有一種動物有類似的頜骨和肌肉:大熊貓，它們也吃難以咀嚼的厚植被，如竹筍。

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.

事實上，這項新的研究表明，袋鼠的下巴在形狀和功能上更像今天的大熊貓，而不是現(xiàn)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.

科學家們已經(jīng)猜測，這些巨型袋鼠的下顎使它們能夠吃掉難以咀嚼的植物。米切爾決定通過確定頭骨能抵抗多少力來檢驗這個理論。

(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，他創(chuàng)建了一個短臉袋鼠頭骨的三維數(shù)字模型，并模擬了游戲中的機械力。米切爾發(fā)現(xiàn)，這種古老動物的巨大顴骨支撐著巨大的肌肉，在巨大的咬合過程中可以防止動物的下巴脫臼。

The bones on the front and top of its skull formed an arch that helped keep the muscles from twisting.

它頭骨前部和頂部的骨頭形成一個拱形，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.

根據(jù)這項研究，這只已經(jīng)滅絕的袋鼠的生理學表明，它已經(jīng)適應(yīng)了利用那些比現(xiàn)在活著的澳大利亞草食動物更難咀嚼的食物。相比之下，現(xiàn)代袋鼠更喜歡草、花、蕨類植物和苔蘚。