Ann Arbor: Around 41,000 years ago, Earth’s magnetic field weakened dramatically during a phenomenon known as the Laschamps excursion, dropping to just 10 percent of its usual strength.
Normally, the magnetic field shields the planet from harmful cosmic and solar radiation, but its collapse left regions such as Europe and northern Africa exposed to intense ultraviolet (UV) radiation.
A new study by researchers at the University of Michigan suggests that early Homo sapiens survived this extreme solar exposure through innovative behavioral and technological adaptations, while Neanderthals, lacking similar strategies, may have been more vulnerable.
Ochre as Prehistoric Sunscreen
One key survival tool was ochre, a red, iron-rich pigment traditionally used in cave art and body decoration. Archaeological evidence shows early humans applied ochre to their skin, and experimental studies indicate it may have acted as a natural sunscreen, providing crucial protection from damaging UV rays during one of Earth’s most intense solar exposures.
Tailored Clothing and Strategic Shelters
Beyond ochre, early humans developed tailored clothing, crafted with tools such as needles, scrapers, and awls. Unlike simple coverings, these fitted garments offered warmth and additional UV protection.
Caves and natural shelters were also increasingly utilized, giving further protection from solar radiation. Together, these strategies allowed Homo sapiens to survive under environmental stress that would have been hazardous for other species.
The study provides a fresh perspective on Neanderthal extinction around 40,000 years ago. Lacking comparable adaptations, Neanderthals may have been exposed to higher levels of UV radiation and cosmic rays.
The geographic overlap of high-exposure regions with early human sites suggests that behavioral and technological innovations gave Homo sapiens a critical survival advantage.
While the findings are correlational, they shed light on our ancestors’ ingenuity and resilience. “These ancient strategies-prehistoric sunscreens, tailored clothing, and clever use of shelters, highlight the adaptability that allowed humans to thrive under extreme environmental stressors,” said the study’s lead researcher.
The research also offers a glimpse into potential future challenges, as fluctuations in Earth’s magnetic field could disrupt modern technology and pose risks to human health.
