Placeholder Image

字幕列表 影片播放

  • If you were to go for a walk in the forests of Southeast Asia during the Ice Age, you’d

  • probably see a lot of awesome, and familiar, creatureslike rhinos, tapirs, and hyenas.

  • But an animal once wandered these woods that was unlike anything youve ever seen.

  • About 3 metres tall and weighing up to 500 kilograms, this beast was probably twice the

  • size of a modern gorilla.

  • Scientists call it Gigantopithecus, the greatest great-ape that ever was.

  • And for us fellow primates, there are some serious lessons to be learned in how it lived, and

  • why it disappeared.

  • So the story of Gigantopithecus begins with the some of the smallest of physical clues -- teeth.

  • And they weren't found in the field, but in a drug store.

  • In 1935, paleontologist Ralph von Koenigswald was rummaging through apothecary shops in

  • Hong Kong.

  • He was looking for so-called dragon teeth -- the name given to fossil teeth from all

  • sorts of animals that were used in traditional Chinese medicine.

  • And on one of these trips, von Koenigswald found a molar unlike any he’d seen before.

  • The tooth was like that of an ape, broad and flat, but it was a much bigger one from any

  • known species, living or extinct.

  • Von Koenigswald eventually determined that these teeth were of an enormous primate, and

  • he named this new creature Gigantopithecus, orgiant ape.”

  • After this initial discovery, more teeth were found in other medicinal shops, and eventually

  • a few fossil jawbones were found in a Chinese cave.

  • But that was it.

  • Since then, weve found more jaws and thousands of teeth.

  • But no other parts of the giant ape’s body have ever been discovered.

  • Even though we have so little of its anatomy to study, weve managed to figure out a

  • lot about Gigantopithecus just from those teeth and jaws.

  • For starters, it turns out there were three species of this giant ape, the earliest of

  • which dates back about 9 million years, to the Miocene epoch.

  • But the most recent, and by far the largest of them, was Gigantopithecus blacki

  • It lived from 2 million to 100 thousand years ago during the Pleistocene epoch, in what’s

  • now south China and Vietnam.

  • Of course, the most obvious feature of Gigantopithecus blacki’s teeth is their size.

  • At 2 and a half centimeters wide, the ape’s molars were more than twice the width of a

  • human tooth.

  • But an even closer look at these teeth has revealed much more than just how big this

  • animal was.

  • For one thing, scientists have been able to use them to figure out who its closest living

  • relatives are.

  • In 2008, a team of anthropologists studied the thickness of the enamel on ten Gigantopithecus

  • teeth, as well as the shape of the hard tissue underneath it, called the dentin.

  • They found that the structure and the composition of the fossil teeth were most similar to those

  • of the only great apes left in Asiathe orangutans.

  • Which iskind of strange.

  • Because orangutans are arboreal; they spend most of their time high in the trees.

  • But Gigantopithecus was way too big to do that.

  • So, scientists think it mustve been a ground-dweller.

  • Which raises a new set of questions.

  • For one thing, what does a 500-kilogram primate eat?

  • Well, its teeth were flat and wide, but its jaws were deep and strongand all of these

  • features are associated with feeding on tough, fibrous plants.

  • Microscopic plant fossils, called phytoliths, have also been recovered from some teeth,

  • showing that it fed on grasses -- including possibly bamboo -- as well as seeds and fruit.

  • But while these physical clues can tell us a lot about the diet of this extinct ape,

  • the chemical composition of its teeth can also reveal to us where it lived.

  • And possibly, why it disappeared.

  • The trail of clues here begins with isotopes of carbon.

  • Different kinds of plants produce different ratios of carbon isotopes during photosynthesis,

  • depending on what kinds of environments they live in.

  • For example, plants that live in cool, humid climates are typically whatre known as

  • C3 plants, because their way of photosynthesizing results in a 3-carbon acid that has its own

  • unique combination of carbon isotopes.

  • But plants that grow in hotter, drier climates are usually C4, because they do photosynthesis

  • in a slightly different way, and produce their own byproducts with their own ratios of carbon.

  • And this is all extremely useful for scientists, because the chemical signatures in these plants

  • are absorbed by the animals that eat them.

  • So by studying the chemistry of Gigantopithecus teeth, researchers can tell not only what

  • kinds of food it ate, but also possibly what its Ice Age habitat was like.

  • And in 2011, paleontologsts from China studied the tooth enamel of Gigantopithecus and found

  • that it fed exclusively on C3 plants -- the ones that tend to grow in cool, humid forests

  • rather than warm, grassy plains.

  • At the same time, though, fossils of other mammals that lived alongside the ape have

  • been studied too -- I’m talking about those rhinos, tapirs, and hyenas I mentioned earlier.

  • And it turns out, they ate some C3 plants, but also C4 plants, which grow in drier, grassy

  • areas.

  • So this suggests that Gigantopithecus probably lived in a mosaic habitat, kind of like a

  • checkerboard of forests and grasslands.

  • But unlike its fellow herbivores, Gigantopithecus preferred to live only under the dense forest

  • canopy and didn’t stray into the open -- much like modern orangutans and mountain gorillas,

  • who are also forest experts.

  • And this specialist lifestyle seemed to work very well, at least for a while.

  • The fossil record shows that Gigantopithecus blacki existed for nearly 2 million years

  • in the forests of southeast Asia.

  • But these primates lived during a time of great change.

  • The Pleistocene is sometimes called the Ice Age, when glaciers were constantly ebbing

  • and flowing across the land, holding moisture when they froze and releasing it again when

  • they thawed.

  • This constant fluctuation meant that Pleistocene habitats were in an ongoing state of flux.

  • Things could be warm and humid for 20,000 or 100,000 years or so, which would allow

  • forests to grow.

  • But then it would freeze again and draw all the moisture back up to higher latitudes,

  • and grasslands would spread.

  • Somehow, Gigantopithecus managed to survive the first few of these glacial periods, but

  • 100 thousand years ago, in the Middle Pleistocene, something changed.

  • Another cold snap occurred that was simply too severe for the apes to survive.

  • As the ice expanded, so did the grasslands, shrinking the forests of Southeast Asia.

  • Without the habitat it needed to survive, populations of Gigantopithecus shrank dramatically.

  • And by 100,000 years ago, the last of Gigantopithecus had vanished.

  • So Gigantopithecus managed to thrive for as long as it did because it was a specialist

  • -- it found the right combination of food and habitat to suit its probably massive needs.

  • But in the end, its specialized habits left it vulnerable in an ever-changing world.

  • And in this way, its predicament is similar to that of many modern animals, including

  • its closest living relatives, the orangutans.

  • Orangs are forest specialists, too, only found in the dense jungles of Borneo and Sumatra.

  • But for decades their unique forest homes have been reduced by things like logging and

  • wildfires.

  • With much of their habitat gone, all three species of orangutan are now considered critically

  • endangered.

  • Still, some researchers hold out hope that we can help these distant cousins of Gigantopithecus

  • -- and of us! -- by continuing to learn the story of the greatest ape that ever lived.

  • Now, what do you want to know about the story of life on Earth?

  • Let us know in the comments.

  • And don’t forget to go to youtube.com/eons and subscribe!

  • But don’t stop here!

  • Do yourself a favor and check out some of our sister channels from PBS Digital Studios!

If you were to go for a walk in the forests of Southeast Asia during the Ice Age, you’d

字幕與單字

影片操作 你可以在這邊進行「影片」的調整,以及「字幕」的顯示

B1 中級 美國腔

世界上最大的猿发生了什么?(What Happened to the World's Greatest Ape?)

  • 1 0
    joey joey 發佈於 2021 年 05 月 03 日
影片單字