Neanderthals’ Inner Ears Reveal Ancient Population Collapse

A team of scientists has uncovered new evidence suggesting that Neanderthals — our closest extinct relatives — experienced a catastrophic population collapse tens of thousands of years ago. The discovery was made by studying an unlikely source: the structure of their inner ears. These findings may significantly reshape how researchers understand Neanderthal evolution and eventual extinction.

The study, led by an international group of anthropologists and geneticists, utilized high-resolution CT scans of Neanderthal fossils found across Europe. By examining variations in the semicircular canals of the inner ear — a structure responsible for balance — researchers identified a pattern indicative of a dramatic reduction in population size. The findings were detailed in a report published by Earth.com.

According to the research team, the observed anatomical changes align with what scientists call a “genetic bottleneck” — a sharp decrease in genetic diversity due to a significant drop in the number of individuals within a population. Such events leave behind distinctive evolutionary signatures that can be detected in the physical traits of species, particularly in stable and well-protected structures like the inner ear.

The timing of this suspected collapse is estimated to have occurred between 100,000 and 70,000 years ago, during a period marked by dramatic climate fluctuations across Eurasia. Shifting temperatures, food scarcity, and competition with other hominin species — such as Denisovans and early Homo sapiens — likely contributed to the dramatic downturn in Neanderthal numbers.

What sets this study apart is its use of the inner ear as a biological marker of population dynamics. Unlike external bones, which can degrade or be influenced by environmental factors, the inner ear is housed deep within the skull and remains well-preserved in fossilized remains. This anatomical resilience allows researchers to extract reliable evolutionary data spanning tens of thousands of years.

The data further suggest that Neanderthals, although spread widely across Europe and parts of the Middle East, lived in small, fragmented populations. This demographic fragility made them especially vulnerable to extinction pressures, as isolated groups were less likely to recover from disease outbreaks, environmental shocks, or genetic inbreeding.

Researchers now plan to apply the same methodology to other archaic human populations, hoping to determine whether similar population bottlenecks occurred elsewhere in our evolutionary tree. These efforts may reveal broader patterns that shaped the fate of our ancestors and shed light on how Homo sapiens managed to endure while others faded into prehistory.

For scientists, the study highlights the power of anatomical microstructures in revealing ancient evolutionary events. For the public, it offers a haunting reminder that survival is never guaranteed — not even for species that once dominated their ecosystems for hundreds of thousands of years.