North America’s Footprints: Humans 21,000 Years Ago

| Mysterious
October 15, 2024

Footprints at a site have been revealed to be the oldest known footprints and the oldest firm evidence of humans anywhere in the Americas, showing that people lived there 21,000 to 23,000 years ago, several thousand years earlier than scientists once believed.

 

“It’s the earliest unequivocal evidence of humans in the Americas,” said study lead author Matthew Bennett, a professor of environmental and geographic sciences at Bournemouth University in the United Kingdom.

Fossilized human footprints have been found throughout the east of the national park, where a now-dry “paleo-lake” bed supplies the gypsum-rich soil that is eroded by wind to create massive white dunes for which the region is famous.

Any traces of early human occupation had been questioned because they were based on what appeared to be stone tools that could have formed naturally, Bennett said, or on artifacts that could have been moved from their original stratigraphic layers.

Fossil footprints show humans were in North America more than 21,000 years ago

The team has studied the footprints in White Sands National Park for years, digging trenches and following the tracks with ground-penetrating radar. NPS, USGS and Bournemouth University

“A footprint is a really good, unambiguous piece of information,” he said. “That’s the importance of this site: we know they were there.”

The footprints, in turn, would lend credibility to other evidence of early humans in the Americas.

“Now you can look at older sites and say, ‘We know they were there during the last glacial maximum,’ so maybe some of these older sites are reliable, too,” he said.

The term “Last Glacial Maximum” is how scientists refer to the height of the last ice age, about 20,000 to 26,000 years ago.

There has long been debate about whether humans reached the Americas by a northern route from Siberia before or after the Last Glacial Maximum, when vast ice sheets would have made migration along the Pacific coast or across western Canada impossible.

The ancient footprints at White Sands answer that question, suggesting they may have arrived as long as 30,000 years ago, thousands of years before the height of the Ice Age, Bennett said.

Fossil footprints show humans were in North America more than 21,000 years ago

The location of the new excavations was on the edge of a wetland when the footprints were left between 21,000 and 23,000 years ago. Karen Carr

White Sands is now mostly desert, but it was a lush wetland at the time the tracks were left and was populated by mammoths, ground sloths, bovids (cattle), and wild camels, as well as the Stone Age humans who hunted them.

The footprints, which are interspersed with animal tracks, show that people must have lived there for at least 2,000 years, Cornell University archaeologist Thomas Urban, a co-author of the study, said in an email.

“There are multiple layers of footprints spanning a significant amount of time, suggesting a sustained human presence in the area during the Last Glacial Maximum, rather than a single event,” he said.

Urban developed the noninvasive use of ground-penetrating radar to reveal footprints beneath the surface and show researchers the best places to dig.

The smaller footprints left by adolescents and children outnumber those of adults, Urban said, possibly because they were engaged in tasks that involved simple labor, rather than skilled tasks like hunting.

Fossil footprints show humans were in North America more than 21,000 years ago

New research into ancient footprints at White Sands National Park establishes that they are the oldest known evidence of humans in North America. NPS, USGS and Bournemouth University

“Their presence is simply part of everyday life and is to be expected,” he said. Their activities may have ranged from play to domestic tasks, such as gathering food, water and raw materials for their hunter-gatherer community.

Geologist Cynthia Liutkus-Pierce of Appalachian State University in North Carolina, who has studied ancient human footprints in Tanzania and was not involved in the White Sands research, said it was often difficult to date exactly when fossilized footprints were made, especially when they were pressed into layers of mud, as at White Sands, and not volcanic ash, which is easier to date.

“It’s great to see that this team was able to constrain the formation date of the footprint using radiocarbon dates from the top and bottom [layers],” he said in an email.

Unlike bones or artifacts, footprints are unique because they record fossilized behavior, and their analysis can yield clues about the imprinters.

“Human footprints give us insight into the lives of our ancestors and, in this case, provide detailed information about their daily activities and social dynamics,” Liutkus-Pierce said.

Review: Top 10 Healthcare Services in the USA

The U.S. healthcare industry is a complex ecosystem of providers, insurers, and technology-driven services, delivering critical care to millions. In 2025, the sector is shaped by rising costs (projected at $4.9 trillion in 2023), technological innovation, and a focus on patient-centric care. Below is a detailed review of the top 10 healthcare services in the USA, based on market presence, patient outcomes, and industry impact.

1. HCA Healthcare

HCA Healthcare, based in Nashville, Tennessee, is the largest health system, operating 220 hospitals and over 40,000 staffed beds across 20 states. Known for comprehensive services, including emergency care, surgery, and specialty treatments, it generates significant net patient revenue. Its scale and advanced technology adoption ensure high-quality care, though accessibility varies by region.

2. Universal Health Services (UHS)

UHS manages 183 hospitals across 40 states, with over 21,000 beds, focusing on acute care and behavioral health. Its facilities in Texas, Florida, and California provide diverse services, from trauma care to psychiatric treatment. UHS’s emphasis on mental health integration aligns with 2025 trends, though high costs can be a barrier.

3. Encompass Health Corporation

With 164 hospitals, Encompass is the largest operator of rehabilitation hospitals, offering specialized post-acute care for stroke, brain injury, and spinal cord injury patients. Based in Birmingham, Alabama, it operates in 37 states, delivering measurable outcomes through therapy-focused programs. Its niche focus limits broader service scope.

4. CommonSpirit Health

A Catholic-affiliated system with 142 hospitals, CommonSpirit provides acute care, outpatient services, and telehealth across 21 states. It excels in community health programs and equitable access, serving underserved populations. Its integration of AI for diagnostics enhances efficiency, but merger-related challenges can affect consistency.

5. Ascension Health

Ascension operates 139 hospitals, focusing on primary care, oncology, and cardiology. With a mission-driven approach, it serves low-income communities through charity care programs. Its adoption of value-based care (VBC) models, projected to cover 90 million lives by 2027, improves outcomes but faces staffing shortages.

6. Kaiser Permanente

Kaiser Permanente is a leading integrated healthcare provider, combining insurance and care delivery for 12.5 million members. Its ACA marketplace plans are top-rated for affordability and quality, with low deductibles and strong preventive care. Operating in eight states, its HMO model ensures coordinated care but limits patient choice.

7. Aetna (CVS Health)

Aetna, under CVS Health, provides health insurance and healthcare services, covering 39 million lives. Its ACA plans offer competitive premiums and broad networks, with telehealth and pharmacy integration via CVS. Aetna’s focus on chronic disease management and AI-driven care navigation boosts outcomes, though rural access is limited.

8. Mayo Clinic

Mayo Clinic, based in Rochester, Minnesota, is renowned for specialized care in oncology, cardiology, and neurology. With 70,000 staff and three major campuses, it serves 1.3 million patients annually. Its research-driven approach and high patient satisfaction earn it top rankings, but costs and geographic reach are drawbacks.

9. Cleveland Clinic

Cleveland Clinic, with 23 hospitals, is a leader in cardiac care and medical innovation, serving patients across Ohio, Florida, and Nevada. Its adoption of cloud computing and AI for diagnostics enhances precision medicine. High costs and limited national presence restrict accessibility for some.

10. Blue Cross Blue Shield (BCBS)

BCBS, a federation of 34 independent companies, insures 115 million Americans, offering PPO, HMO, and EPO plans. Its ACA marketplace plans are widely available, with strong provider networks and wellness programs. BCBS’s focus on digital health tools and equitable access is notable, though premiums vary by state.

Choosing the Right Service

Selecting a healthcare service depends on location, medical needs, and budget. HCA and UHS offer broad hospital-based care, while Kaiser and Aetna excel in integrated insurance and delivery. Mayo and Cleveland Clinic are ideal for specialized treatments, and BCBS provides flexible insurance options. Compare costs (e.g., average ACA premium: $635/month), provider networks, and patient reviews on platforms like Healthgrades or U.S. News. With 26 million uninsured Americans and rising costs, prioritize services with telehealth, preventive care, and VBC to maximize value.

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