Researchers: Oldest Human Footprints in North America Are in New Mexico
2021-09-28
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1Footprints discovered in New Mexico suggest that early humans were in North America around 23,000 years ago, researchers reported recently.
2The fossilized footprints were found in a dry lake in White Sands National Park in 2009.
3Scientists at the U.S. Geological Survey recently studied seeds stuck in the footprints to estimate their age.
4Evidence suggested they were from 21,130 to 22,800 years ago.
5The findings may help scientists answer a basic question:
6When did people first arrive in the Americas, after spreading out from Africa and Asia?
7Most scientists believe the migration path included land, now underwater, that linked Asia with what is now the state of Alaska.
8Past research has suggested that humans arrived in the Americas from 13,000 to 26,000 years ago.
9Such findings were based on different kinds of evidence - including stone tools, fossil bones and genetic studies.
10The recent study gives a more solid baseline for when humans were in North America.
11Fossil footprints are more direct, clearer evidence than "cultural artifacts, modified bones, or other more conventional fossils," the researchers wrote in the publication Science.
12"What we present here," they said, "is evidence of a firm time and location."
13Location means a place or position.
14Based on the size of the footprints, researchers believe that some were made by children who lived during the last ice age.
15David Bustos, the park's resource program manager, saw the first footprints in ancient wetlands in 2009.
16He and others found more in the park over the years.
17"We knew they were old, but we had no way to date the prints before we discovered some with (seeds) on top," he said.
18Bustos said the researchers had to work quickly and carefully to secure pieces of the footprints for study.
19The footprints were made of extremely fine earth material and could easily be damaged.
20"The only way we can save them is to record them - to take a lot of photos and make 3D models," he said.
21Earlier 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.
22I'm John Russell.
1Footprints discovered in New Mexico suggest that early humans were in North America around 23,000 years ago, researchers reported recently. 2The fossilized footprints were found in a dry lake in White Sands National Park in 2009. Scientists at the U.S. Geological Survey recently studied seeds stuck in the footprints to estimate their age. Evidence suggested they were from 21,130 to 22,800 years ago. 3The findings may help scientists answer a basic question: When did people first arrive in the Americas, after spreading out from Africa and Asia? 4Most scientists believe the migration path included land, now underwater, that linked Asia with what is now the state of Alaska. 5Past research has suggested that humans arrived in the Americas from 13,000 to 26,000 years ago. Such findings were based on different kinds of evidence - including stone tools, fossil bones and genetic studies. 6The recent study gives a more solid baseline for when humans were in North America. 7Fossil footprints are more direct, clearer evidence than "cultural artifacts, modified bones, or other more conventional fossils," the researchers wrote in the publication Science. 8"What we present here," they said, "is evidence of a firm time and location." 9Location means a place or position. 10Based on the size of the footprints, researchers believe that some were made by children who lived during the last ice age. 11David Bustos, the park's resource program manager, saw the first footprints in ancient wetlands in 2009. He and others found more in the park over the years. 12"We knew they were old, but we had no way to date the prints before we discovered some with (seeds) on top," he said. 13Bustos said the researchers had to work quickly and carefully to secure pieces of the footprints for study. The footprints were made of extremely fine earth material and could easily be damaged. 14"The only way we can save them is to record them - to take a lot of photos and make 3D models," he said. 15Earlier 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. 16I'm John Russell. 17Christina Larson reported on this story for the Associated Press. John Russell adapted it for Learning English. Caty Weaver was the editor. 18________________________________________________ 19Words in This Story 20footprint - n. a track or mark left by a foot or shoe 21fossilized - adj. having been changed into a fossil. A fossil is something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times 22artifact - n. a simple object (such as a tool or weapon) that was made by people in the past 23modify - v. to change some parts of (something) while not changing other parts 24conventional - adj. used and accepted by most people : usual or traditional