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Footprints discovered in New Mexico suggest that early humans were in North America around 23,000 years ago, researchers reported recently.
研究人员最近报告说，在新墨西哥州发现的足迹表明，早期人类大约在2.3万年前生活在北美。
The fossilized footprints were found in a dry lake in White Sands National Park in 2009.
这些足迹化石是2009年在白沙国家公园的一个干涸的湖泊中被发现的。
Scientists at the U.S. Geological Survey recently studied seeds stuck in the footprints to estimate their age.
美国地质调查局的科学家最近研究了留在足迹中的种子，以估计这些足迹产生的年代。
Evidence suggested they were from 21,130 to 22,800 years ago.
有证据表明，这些足迹产生于21130年至22800年前。
The findings may help scientists answer a basic question: When did people first arrive in the Americas, after spreading out from Africa and Asia?
这些发现可能会帮助科学家回答一个基本问题：人类从非洲和亚洲扩散后，是什么时候第一次抵达美洲的？
Most scientists believe the migration path included land, now underwater, that linked Asia with what is now the state of Alaska.
大多数科学家认为，迁徙路线包括陆地，现在是在水下，它把亚洲与现在的阿拉斯加州连接起来了。
Past research has suggested that humans arrived in the Americas from 13,000 to 26,000 years ago.
过去的研究表明，人类在1.3万年到2.6万年前抵达美洲。
Such findings were based on different kinds of evidence—including stone tools, fossil bones and genetic studies.
这些发现基于不同种类的证据——包括石器、骨骼化石和基因研究。
The recent study gives a more solid baseline for when humans were in North America.
最近的研究为人类在北美生活的时间提供了一个更可靠的基线。
Fossil footprints are more direct, clearer evidence than "cultural artifacts, modified bones, or other more conventional fossils," the researchers wrote in the publication Science.
研究人员在《科学》杂志上写道，足迹化石是比“文化手工制品、改良过的骨骼或其他更传统的化石”更直接、更清晰的证据。
"What we present here," they said, "is evidence of a firm time and location."
他们说：“我们在这里展示的是可以反映确切时间和地点的证据。”
Location means a place or position.
“Location”指的是地点或位置。
Based on the size of the footprints, researchers believe that some were made by children who lived during the last ice age.
根据足迹的大小，研究人员认为，有些足迹是生活在上一个冰河时代的儿童留下的。
David Bustos, the park's resource program manager, saw the first footprints in ancient wetlands in 2009.
该公园的资源项目经理戴维·布斯托斯于2009年在古代湿地发现了第一批足迹。
He and others found more in the park over the years.
多年来，他和其他人在公园里发现了更多足迹。
"We knew they were old, but we had no way to date the prints before we discovered some with seeds on top," he said.
他说：“我们知道这些足迹很古老，但在我们发现一些上面有种子的足迹之前，我们无法确定它们的年代。”
Bustos said the researchers had to work quickly and carefully to secure pieces of the footprints for study.
布斯托斯说，研究人员必须迅速而谨慎地工作，以确保足迹碎片可供研究。
The footprints were made of extremely fine earth material and could easily be damaged.
足迹是由极其精细的泥土材料制成的，很容易损坏。
"The only way we can save them is to record them—to take a lot of photos and make 3D models," he said.
他说：“我们保存它们的唯一方法就是记录它们——拍很多照片，制作3D模型。”
Earlier digs in White Sands National Park have uncovered fossilized tracks left by a saber-toothed cat, dire wolf, Columbian mammoth and other ice age animals.
在白沙国家公园的早些挖掘中发现了剑齿猫、恐狼、哥伦比亚猛犸象和其他冰河时代动物留下的足迹化石。
I'm John Russell.
约翰·拉塞尔为您播报。
译文为可可英语翻译，未经授权请勿转载！
