Study Reveals the Surprising and Twisty Path Our Ancestors Took to Develop an Upright Stance

Mammals didn't walk upright until late—here's what fossils reveal

The shift from lizard-like sprawl to upright walking in mammals wasn’t a smooth climb up the evolutionary ladder. Instead, it was a messy saga full of unexpected detours. Using new bone-mapping tech, researchers discovered that early mammal ancestors explored wildly different postures before modern upright walking finally emerged—much later than once believed.

Study reveals the surprising and twisty path our ancestors took to develop an upright stance

For over a century, scientists have puzzled over a fundamental mystery in our evolutionary history: how did mammals go from sprawling like lizards to striding like cats and dogs? This transition—from a sprawled stance (like a lizard) to an upright (parasagittal) posture—marked a pivotal moment in mammal evolution.

Why mammals don’t crawl like lizards—and the surprising path that got us here

Scientists have long wondered how mammals, including humans, evolved to walk with their legs under their bodies instead of splayed out to the sides like lizards. This upright stance, called a parasagittal posture, helps animals move more efficiently and is key to the way all modern mammals—from moles to whales to people—get around. For more […] The post Why mammals don’t crawl like lizards—and the surprising path that got us here appeared first …

From Reptile-like to Upright: Unraveling the Dynamic Evolution of Mammalian

The evolutionary journey from sprawling, reptile-like postures to the upright limb stance characteristic of modern mammals marks one of the most profound anatomical and functional transitions in vertebrate history. A groundbreaking study published on June 24th, 2025 in the open-access journal PLOS Biology challenges long-standing paradigms about this pivotal shift. Conducted by Dr. Robert Brocklehurst, Professor Stephanie Pierce, and colleagues …