Were our ancestors more like us than we think? Unearthed in New Mexico, tracks show generations living in the area thousands of years before many scientists believed it possible.
Ancient footsteps in sand rewrite history
This undated photo made available by the National Park Service in September 2021 shows fossilized human fossilized footprints at the White Sands National Park in New Mexico. According to a report published in the journal Science on Thursday, Sept. 23, 2021, the impressions indicate that early humans were walking across North America around 23,000 years ago, much earlier than scientists previously thought. © NPS Glossary
Giant sloth - At White Sands, footprints have been found inside the paw prints of this enormous prehistoric animal. Palaeontologist Andrew Milner says: "There’s no evidence of hunting here… Maybe ground sloths were fun to harass? Who knows."
Radiocarbon dating - Decaying radiocarbon in organic matter is used by archaeologists to date artefacts. In this case, scientists dated seeds found with the footprint fossils.
Ice age - A long period of time in which global temperatures are extremely cold.
Clovis culture - In the 1930s, stone tools were discovered near Clovis, New Mexico. In 2014, DNA testing at a burial site in Montana showed the Clovis people were closely related to modern Native Americans.
Paleobiologist - A scientist that studies the fossilised remains of dead biological life.
Deep time - A term often used to refer to the millions of years before recorded history.
Stone tools - In Kenya, massive hammers and anvils have been found that predate the earliest human, suggesting our non-human ancestors may have been more sophisticated than was thought.
Flutes - Researchers speculate these instruments may have been used for rituals, recreation or hunting. Music may have been one of the creative advantages modern humans had over Neanderthals, who began to die out around this time.
Speleologists - Scientists who study the geology, biology and archaeology of caves.
Chauvet Cave - The cave has been sealed off to prevent damage to the paintings. In 2015, a nearly full-scale replica of the cave was opened to the public, where the art and ambience has been faithfully reproduced.