Hi. Before we get started, I wanted to acknowledge that right now, PBS is at risk. The US government is considering devastating funding cuts that would jeopardize our ability to produce shows like this and many others.

嗨 在我们开始之前，我想承认，PBS目前正处于危险之中。 美国政府正在考虑毁灭性的资金削减，这将危及我们制作这样的节目和许多其他节目的能力。

If you live in the US and are interested in supporting PBS's mission, visit ProtectMyPublicMedia.org to make your voice heard.

如果您居住在美国并且有兴趣支持PBS的使命，请访问ProtectMyPublicMedia.org以表达您的声音。

Thanks, now onto the video. Big news, dino lovers, and I mean big news.

谢谢，现在进入视频。 大新闻，恐龙爱好者，我的意思是大新闻。

Walking With Dinosaurs is back on PBS after 25 years, bringing these iconic creatures to life with the latest research and state of the art visual effects. Head to the link in the description to learn more. In 1842, a new term appeared in the scientific literature: dinosaurs, maybe you've heard of them.

《与恐龙同行》时隔25年重返PBS， 利用最新的研究和最先进的视觉效果将这些标志性生物带入生活。 前往描述中的链接以了解更多信息。 1842年，一个新的术语出现在科学文献中：恐龙，也许你听说过它们。

The term was coined to refer to a collection of strange, extinct reptilian land animals whose bones and teeth had been turning up in mines and quarries in England, as the country rapidly industrialized. Biologist Richard Owen place these huge, bizarre animals in a distinct group of their own, which he called dinosauria, or the terrible lizards. The first dinosaurs to be recognized in Owen's new grouping, included such lumbering giants as Megalosaurus, Iguanodon, and Hylaeosaurus. But there was one type of newly discovered giant reptile that Owen excluded from dinosauria, one whose bones seemed so huge that he felt it didn't fit in, even with this new group of big monsters that were already blowing people's minds.

这个词是用来指一群奇怪的， 随着英国迅速工业化，已经灭绝的爬行动物的骨头和牙齿出现在英格兰的矿山和采石场中。 生物学家理查德·欧文将这些巨大而奇怪的动物归入了一个独特的群体，他称之为蜥蜴，或可怕的蜥蜴。 欧文的新物种群中第一批被发现的恐龙包括巨型龙、鬣蜥和海龙等笨重的庞然大物。 但欧文将一种新发现的巨型爬行动物排除在恐龙群之外， 他的骨头看起来如此之大，以至于他觉得它不适合，即使是和这群已经让人们震惊的新怪物在一起。

Today, we know the group Owen left out as the sauropods, the largest animals that ever walked the Earth. But for Owen, who was also the first to formally describe a sauropod skeleton, it was almost impossible to picture something that big walking on land. So instead of classifying it as a dinosaur, he named it Cetiosaurus, or whale-lizard, assuming it must have been some kind of gigantic sea monster.

今天，我们知道欧文遗漏的蜥脚类动物是地球上有史以来最大的动物。 但对于欧文来说，他也是第一个正式描述蜥脚类恐龙骨架的人， 几乎不可能想象有那么大的东西在陆地上行走。 因此，他没有将其归类为恐龙，而是将其命名为鲸蜥，假设它一定是某种巨大的海怪。

Now, in the years since, we've learned a lot about these so-called whale-lizards, including that they really are dinosaurs, and they really did roam the plains and forests of Mesozoic earth, smashing through what we once thought were the limits of body size on land. But we can't judge Owen too hard for getting sauropods so wrong, because even after all this time, they still sometimes seem just too big to make sense.

现在，在此后的几年里，我们对这些所谓的鲸蜥有了很多了解，包括它们确实是恐龙， 它们确实在中生代的平原和森林中漫游，打破了我们曾经认为的陆地上体型的限制。 但我们不能因为欧文对蜥脚类恐龙的错误而过于严厉地评判欧文，因为即使经过了这么长时间， 它们有时仍然看起来太大了，没有意义。

How did these uniquely large land animals actually live with their anatomy and physiology pushed to such extremes? Well, sauropods, unprecedented gigantism came with some equally massive costs. And while we understandably marvel at the grandeur of these titans of the deep past, once you dive into the details of what it took to be gigantic, one thing becomes clear. It's not easy being big.

这些独特的大型陆地动物实际上是如何在解剖学和生理学被推向如此极端的情况下生活的？ 嗯，蜥脚类动物，前所未有的恐龙灭绝也带来了同样巨大的代价。 虽然我们可以理解地惊叹于这些远古巨人的宏伟，但一旦你深入了解细节是什么让它们巨大， 有一件事变得清楚了。 成为大人物并不容易。

Sauropods are in a league entirely their own. There are no known land animals, living or extinct, that even come close to the size of the largest sauropod dinosaurs. The very largest of them, which belong to a group known as the titanosaurs, are estimated to have pushed up to 35 to 40m in length, and may be over 70 tons in weight.

蜥脚类动物完全属于自己的一类。 没有一种已知的陆地动物，无论是现存的还是灭绝的，体型能接近最大的蜥脚类恐龙。 其中最大的属于泰坦龙，据估计长度已达到35至40米， 重量可能超过70吨。

For comparison, the next largest non-sauropod land animals in history that we know of barely approached a third of this size. So we actually have no good comparisons in any other land animal group before or since. Which is extremely unusual in natural history we often see similar lifestyles, and body plans emerge convergently across even distantly related groups in different places and at different times.

相比之下，我们所知的历史上第二大的非蜥脚类陆地动物的体型几乎没有达到这个体型的三分之一。 所以我们在之前和之后都没有很好的比较。 这在自然史上极其不寻常，我们经常看到相似的生活方式， 即使是在不同地点和不同时间的远亲群体中，身体平面也会趋同。

Like cetaceans and ichthyosaurs, crabs and false crabs, or trees and other trees. But sauropods are a unique evolutionary case, and there's probably a reason that no other animals have ever come close to their proportions.

就像鲸目动物和河豚、螃蟹和假蟹，或者树木和其他树木。 但蜥脚类动物是一个独特的进化案例，这可能是有原因的，没有其他动物能够接近它们的比例。

When you scale up to that degree on land, your biology has to get pretty weird to cope. So maybe it's not surprising that it took a while for scientists to really accept that sauropod dinosaurs did, in fact, somehow haul themselves around on land, and that they weren't aquatic or semi-aquatic giant supported by the buoyancy of water around them.

当你在陆地上扩大到这种程度时，你的生物学必须变得非常奇怪才能应付。 所以，科学家们花了一段时间才真正接受蜥脚类恐龙确实有， 以某种方式在陆地上拖着自己，它们不是水生或半水生的庞然大物，靠周围水的浮力支撑。

Because merely taking a single step seemed impossible without their legs shattering under their own weight. This is simply a problem of physics, and one of the primary mysteries, that paleontologists have had to grapple with to make sauropods make sense.

因为仅仅迈出一步，他们的腿就不可能不被自己的重量压垮。 这只是一个物理问题，也是古生物学家必须努力解决的主要谜团之一，以使蜥脚类动物有意义。

And despite all the scientific advances made over the years, and all the sauropod fossils discovered, we still struggle to model the biomechanics of such large creatures taking a single step without breaking apart. But in 2022, researchers made a pretty important leap in figuring out how on Earth they walked on Earth. The scientists decided to test a potential explanation, built-in feet cushions at the bottom of sauropods huge, column-like legs, kind of like a larger version of the pads found on the feet of elephants today.

尽管这些年来科学取得了很大的进步，也发现了很多蜥脚类恐龙的化石， 我们仍然很难对如此大型生物的生物力学进行建模，使其迈出一步而不分裂。 但在2022年，研究人员在弄清楚他们如何在地球上行走方面取得了相当重要的飞跃。 科学家们决定测试一种可能的解释，蜥脚类动物巨大的柱状腿底部的内置脚垫， 有点像今天在大象脚上发现的脚垫的更大版本。

Seeing as these structures are made entirely of soft tissues, they don't fossilize well, so they haven't left any proof in the sauropod fossil record. But by analyzing their foot skeletons and fossil tracks, the researchers were able to generate 3-D digital models of the feet of various sauropod species.

由于这些结构完全由软组织组成，因此它们不能很好地缝合， 所以他们没有在蜥脚类恐龙化石记录中留下任何证据。 但通过分析它们的足部骨骼和化石痕迹， 研究人员能够生成各种蜥脚类动物足部的3D数字模型。

This allowed them to test and compare how the feet behaved under the forces generated by different postures, both with and without a soft tissue pad included in the model. They found that without the presence of the pad cushioning and absorbing the forces bearing so much weight, the foot bone simply broke and crumpled, regardless of posture or species.

这使他们能够测试和比较脚在不同姿势产生的力下的表现， 模型中包含有或没有软组织垫。 他们发现，如果没有脚垫的存在来缓冲和吸收承受如此大重量的力，脚部骨头就会断裂并起皱， 不论姿势或种类。