“Early Americans lived among and hunted mammoth, camel, extinct horse and bison as far back as 15,000 years. Now there is mounting evidence for a second breakthrough that will push the history of man in America back to 30,000 years — and possibly further.”
The question of when humans first set foot in the Americas is still hotly debated. Recent fossil and archaeological evidence suggests the first inhabitants arrived tens of thousands of years ago. For instance, humanlike footprints in New Mexico date to about 20,000 years ago (SN: 11/6/21, p. 12). And stone tools found in a cave hint that humans resided in Mexico roughly 30,000 years ago (SN: 7/3/21 & 7/17/21, p. 16). Some archaeologists argue that stones caked with mastodon bone residue that were found in California were tools used by humans or their close relatives around 130,000 years ago, although that claim remains controversial (SN Online: 12/4/20). Pinning down the timeline of human settlement could reveal how people spread across North and South America.