The first " Americans" crossed the land bridge from Asia.

第一批美洲人来自亚洲。

They migrate across the land bridge into Asia, jump over into Europe.

他们跨过陆桥，进入亚洲，然后进入欧洲。

At that time, the Andaman Islands were connected to modern-day Myanmar by a land bridge.

当时，安达曼群岛通过一座大陆桥与今天的缅甸相连。

There's no evidence that there was this huge land bridge across the Atlantic.

没有证据表明，有一座巨大的陆桥横跨大西洋。

Sometime after 4 million years ago, ancient equid species began trotting across the Bering land bridge.

在 400 万年前的某个时候，古老的马科物种开始穿越白令陆桥。

That was a few thousand years before rising sea levels covered the Bering land bridge between Asia and North America.

在那之后几千年，海平面才上升覆盖亚洲和北美之间的白令大陆桥。

IT CAME WITH THE LAND BRIDGE AND SURVIVED THE CHANGES.

它与陆桥一起出现并在变化中幸存下来。

So they decided that Indians had reached North America by some unknown land bridge.

因此他们断定印第安人是通过某个未知的陆桥到达北美的。

Ancient texts describe how Prince Rama had the land bridge built to reach his wife across the sea.

古代文献描述了拉玛王子如何建造陆桥以跨海到达他的妻子。

This island -- now known as Wrangel Island -- was once connected to Siberia by land bridges and ice shelves.

这个岛——现在被称为弗兰格尔岛——曾经通过陆桥和冰架与西伯利亚相连。

That land bridge permitted large numbers of animals to begin walking between the continents in one of the biggest mixing of species on record.

因为这座陆地桥，两块大陆之间得以交换物种，也就出现了史上最大规模的生物迁徙之一的记载。

Mustelid migrations across the Bering land bridge continued until around 5 million years ago, when the Bering Strait severed that route.

鼬科动物穿过白令陆桥的迁徙一直持续到大约 500 万年前，当时白令海峡切断了这条路线。

And about a half-million years after that, they crossed the Bering Strait land bridge to spread into Asia, Europe, and Africa.

大约 50 万年后，他们越过白令海峡陆桥，传播到亚洲、欧洲和非洲。

Giant beasts, like the wooly mammoth and giant sloth, died off to be replaced by better adapted creatures that migrated across land bridges from the north.

像长毛猛犸象和巨型树懒这样的巨大动物都灭绝了，取而代之的是适应力更好的生物，它们从北部通过陆桥迁徙而来。

Some geologists believe that it was once a naturally-occurring land bridge which either collapsed into the sea or was engulfed by rising sea levels.

一些地质学家认为，它曾经是一座天然存在的陆桥，要么坍塌入海，要么被上升的海平面吞没。

Which is weird, because scientists think that the land bridge between North and South America probably wasn't complete until about 3 million years ago.

这很奇怪，因为科学家认为北美和南美之间的陆桥可能直到大约 300 万年前才完工。

Soon maps of prehistoric seas were almost solid with hypothesized land bridges, from North America to Europe, from Brazil to Africa, from Southeast Asia to Australia, from Australia to Antarctica.

过不多久，史前海洋的地图上几乎到处都是假想的陆桥，从北美洲到欧洲，从巴西到非洲，从东南亚到澳大利亚，从澳大利亚到南极洲。

Even more awkwardly anomalous was another species of trilobite found in Europe and the Pacific Northwest but nowhere in between, which would have required not so much a land bridge as a flyover.

另一种三叶虫的情况更是反常，它出现在欧洲和美国西北部的太平洋沿岸，而中间地带却不见踪影。这与其说需要一座陆桥，不如说需要一座立交桥。

But the rudimentary skills of mice suggested that the language-critical capacity might exist on a continuum, much like a submerged land bridge might indicate that two now-isolated continents were once connected.

但老鼠的基本技能表明，语言关键能力可能存在于一个连续体中，就像一座被淹没的陆桥可能表明两个现在孤立的大陆曾经是相连的。

These early cats certainly lived in North America, as well as Eurasia, though we don't know if it  was they or their ancestors who made the trek across the Bering land bridge.

这些早期的猫科动物肯定生活在北美以及欧亚大陆，尽管我们不知道是它们还是它们的祖先长途跋涉穿越了白令陆桥。