Neanderthal Pelvis May Explain the Evolution of Male and Female Human Pelvic Shapes

New research on the Neanderthal pelvis may help explain why modern human men and women have such different pelvic shapes. The findings suggest that changes in the male pelvis may have improved walking efficiency by helping absorb and return energy during bipedal movement.

“Until the discovery of a nearly complete male Neanderthal pelvis in the early 1980s at Israel’s Kebara Cave, little was known about the overall anatomy of the Neanderthal pelvis,” said Professor Ella Bean of Ono Academic College and her colleagues.

“The small number of pelvic fragments available at the time suggested significant differences between Neanderthal and modern human pelvises, particularly in males.”

For the new study, the researchers compared the Neanderthal pelvis known as Kebara 2 with another Neanderthal pelvis from Sima de los Huesos in Spain. They also examined 63 modern human male pelvises and 28 modern human female pelvises.

The researchers found that Neanderthal males shared several important pelvic features with modern human females rather than with modern human males.

The most significant difference involved the position of the hip joint, or acetabulum. In modern human males, the hip joint is positioned farther forward in relation to the pelvic brim. This configuration is associated with a shorter and thicker superior pubic ramus, the section of bone extending toward the front of the pelvis.

By contrast, the hip joint in Neanderthal males was positioned farther back. This left a longer, thinner branch of bone, a configuration that is also found in modern human females.

The researchers propose that the forward position of the hips in modern human males may have transformed the pelvis into a natural shock absorber and energy-return system.

“At each stage of bipedal locomotion, the body’s center of gravity moves downward,” said Professor Yoel Ruck of Tel Aviv University.

“This downward movement places stress on the joints and requires energy to lift the body again for the next step.”

According to the researchers’ model, the distinctive shape of the modern male pelvis allows the thigh muscles to buffer the body’s lowered center of gravity. The muscles can store potential energy during a step and release it immediately afterward, helping propel the body upward into the next stride.

“In this way, the pelvis acts as a natural shock absorber and energy-return system,” the researchers explained.

This adaptation may have reduced energy expenditure and improved walking efficiency, offering significant advantages during long-distance travel.

The forward shift in hip position would also have required other structural changes, including a thicker pubic bone and a deeper anterior pelvis capable of withstanding increased mechanical loads.

The scientists suggest that these adaptations may have evolved after the evolutionary split between Neanderthals and Homo sapiens.

They also propose that modern human females retain a more ancestral pelvic configuration because further narrowing or deepening of the pelvis could interfere with the physical demands of childbirth.

“Our research shows that questions about human evolution are not limited to the distant past,” Professor Bean said.

“Understanding the evolution of human walking mechanisms may contribute to modern research in biomechanics, musculoskeletal medicine, rehabilitation, and injury prevention.”

“The perspective provided by Neanderthals can help us better understand the modern human body.”

The study was published online on July 31, 2026, in Scientific Reports.

_____

Y. Ruck et al. A Neanderthal pelvis reveals a specialized human male walking mechanism. Scientific Reports, published online July 31, 2026. doi: 10.1038/s41598-026-59915-8