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The Neanderthals of a Cave in Northern Spain Were Already Making and Reusing Bone Tools in a Standardized and Planned Way

A team of researchers from the University of Burgos and the Atapuerca Foundation has published the first detailed analysis of the bone retouchers found in the Valdegoba cave, in the municipality of Huérmeces (Burgos). This site, occupied by Neanderthals during the Middle Paleolithic, has yielded 38 bone fragments that were used as tools to retouch […]

Scientists Discover that the Increase in Visual Information Was What Allowed the Development of Ape and Human Brains

The research, published in the journal Science, was led by Richard F. Kay, emeritus professor of Evolutionary Anthropology at the Trinity College of Arts & Sciences and at the Nicholas School of the Environment at Duke University. The work, which used a unique collection of skulls mostly from the Natural History Museum of the Duke […]

1.4-Million-Year-Old Footprints Reveal a Giant Human Relative

1.4 Million Year Old Footprint From KenyaA 1.4-million-year-old trail of footprints reveals that a powerful human relative grew nearly as large as us and may have traveled in all-male groups. Eight individuals walked across the wet ground beside an ancient Kenyan lake. Within a short time, sediment buried their footprints and preserved a scene that would remain hidden for roughly 1.4 [...]

The discovery of footprints from a hominid that lived 1.4 million years ago by a Kenyan lake reveals it could reach 180 centimeters in height

An international team of researchers has documented a set of fossilized footprints that offer an exceptional snapshot of the behavior of a group of ancient human relatives who inhabited the shores of a lake in northern Kenya. The recently published study analyzes the imprints belonging to eight individuals of the species Paranthropus boisei, an extinct […]

Scientists May Have Finally Solved One of Human Evolution’s Biggest Mysteries: When Our Ancestors Grew Larger

16 July 2026 at 13:52

For decades, paleoanthropologists have largely agreed that somewhere along the evolutionary course from apelike ancestors to modern humans, our bodies got dramatically larger. However, one lingering mystery has been when this intense growth began.

Did our ancestors gradually grow bigger over millions of years? Did the shift coincide with the emergence of the genus Homo? Or did it occur later, after some of the earliest human species had already appeared?

A new study published in the Proceedings of the National Academy of Sciences (PNAS) argues that the answer is more complex than any single theory has suggested.

Rather than supporting a single long-standing hypothesis, researchers used a sophisticated statistical method to show that human body size likely followed two evolutionary courses simultaneously: a slow, steady increase spanning millions of years, punctuated by a much larger leap in later members of the genus Homo.

The findings help reconcile decades of conflicting research while offering one of the clearest pictures yet of how, and perhaps why, our ancestors evolved into larger-bodied humans.

“Despite its central role in hominin evolution, there is little consensus on how body size increased through time,” researchers write. “We provide strong evidence for a marked size increase in later-occurring Homo, alongside a moderate general increase over time among all hominins.”

Body size is one of the defining characteristics of an organism. In humans and our extinct relatives, it has been linked to everything from brain expansion and walking efficiency to metabolism, hunting behavior, and the ability to travel across increasingly large landscapes. Understanding when body size changed, therefore, helps researchers reconstruct not only what our ancestors looked like, but how they lived.

Yet despite decades of fossil findings, scientists have struggled to agree on the evolutionary pattern behind those changes.

Some previous studies suggested that hominins simply became larger over time. Some contended that body size remained relatively stable until the emergence of Homo. Still others have proposed that the real transformation arose only after early species such as Homo habilis, often regarded as one of the first members of our genus.

According to researchers, one reason for the disagreement is that earlier analyses typically examined these competing ideas independently. They also often failed to account for uncertainties inherent in the fossil record, including disagreements over species classification, differences in body mass estimation methods, and uncertainties in evolutionary relationships among fossil species.

To address those limitations, researchers compiled one of the largest hominin body-size datasets assembled to date, incorporating body mass assessments from 386 fossil specimens representing 21 different taxa.

They then analyzed the data using Bayesian phylogenetic generalized linear mixed models—a statistical approach that accounts for evolutionary relationships while encompassing multiple layers of uncertainty.

The team repeated its analyses across 1,000 different phylogenetic trees and 1,000 separate datasets, allowing them to test whether the overall pattern remained consistent despite uncertainties.

The results pointed to two simultaneous trends.

The first was a modest but persistent increase in body size across the hominin family as a whole. On average, body mass increased by roughly 2 pounds (0.9 kilograms) every million years, suggesting that larger bodies gradually became more common throughout human evolution.

However, the second trend proved far more dramatic.

Instead of all members of Homo becoming substantially larger, the researchers found the strongest evidence for a distinct jump in body size among later members of the genus, particularly species that appeared after Homo habilis. That pattern regularly emerged regardless of how the fossil data were analyzed.

In other words, early members of Homo may not have represented the major biological turning point scientists once assumed.

This finding disputes a common assumption that simply belonging to the genus Homo meant possessing a significantly larger body. Instead, the study suggests that some hallmark features traditionally associated with humans, including larger body size, may have evolved after the genus’s origin.

That interpretation also corresponds to broader changes that occurred later in human evolution.

Researchers note that this period coincides with evidence for more efficient upright walking, greater reliance on meat consumption, and expanding home ranges. Larger bodies may have been both a consequence of and a contributor to those behavioral and ecological shifts.

The study likewise reinforces another growing theme that evolution rarely follows a straight line.

Species such as Homo floresiensis, often nicknamed the “Hobbit” because of its diminutive stature, and Homo Naledi frequently appeared as outliers with unusually small body sizes despite belonging to relatively recent branches of the human family tree. Their existence demonstrates that body size did not simply increase in a uniform march toward modern humans.

Instead, evolution repeatedly experimented with different solutions depending on local environments and ecological constraints.

The researchers also argue that part of the longstanding disagreement over body-size evolution stems from the fossil record itself. Different studies have estimated fossil body masses using different skeletal elements, comparison populations, and statistical techniques, sometimes producing substantially different results for the same individual.

By expressly incorporating those uncertainties into their analysis, rather than treating them as fixed values, the new framework seeks to capture the range of plausible evolutionary scenarios rather than relying on a single interpretation.

Even so, researchers caution that important questions remain unresolved.

Improved fossil discoveries, more accurate body-mass estimation methods, and a better understanding of species relationships could all further refine the picture. The study also does not explicitly account for sexual size differences between males and females, which may have been greater in some early hominin species than in modern humans.

Nevertheless, the wider conclusion is intriguing.

Rather than choosing between competing theories, the evidence suggests both contain elements of the truth.

Body size did increase gradually across the hominin lineage. But the most considerable leap appears to have occurred later, after the earliest representatives of Homo had already evolved.

That conclusion may help settle one of paleoanthropology’s longest-running debates while showing how advances in statistical methods are transforming scientists’ ability to extract new insights from fossils that have often been studied for decades.

“Overall, these findings bring clarity to a fundamental question in human evolution and show how the application of rigorous phylogenetic comparative tools can unlock patterns previously hidden in the fossil record while accounting for multiple sources of uncertainty,” researchers write. “By reconciling conflicting findings within a single framework, our results clarify key evolutionary transitions and highlight the complex nature of body size change in human evolution.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

A Lost Human Lineage May Have Left a Genetic Legacy in People Today

Homoerectus dmanisi Skull PaleontologyHomo erectus may have left a detectable genetic trace in living humans through ancient interbreeding with Denisovans. For much of the 20th century, human evolution was often pictured as a branching tree. One trunk split into separate limbs, and each ancient human relative, or hominin, occupied its own tidy branch. That was the version many [...]

Ancient DNA Reveals the Hidden Origins of China’s Mysterious Shimao Civilization

Carving Stone at Shimao CityAncient DNA from Shimao reveals local origins, broad prehistoric connections, a patrilineal social structure, and gender-specific patterns of human sacrifice. At Shimao, a vast stone-walled settlement in northern China, ancient DNA is filling in details that archaeology alone could not fully resolve. The genetic evidence is helping trace where the people of this late Neolithic [...]

Flores Hobbits' eating habits offer clues about their evolutionary past

9 July 2026 at 23:29

Until about 60,000 years ago, diminutive hominin cousins, Homo floresiensis (affectionately nicknamed Hobbits for obvious reasons), shared the island of Flores with Komodo dragons, pygmy elephants, and giant rats.

Based on the presence of hominin and pygmy elephant bones in the same layers of cave sediment, it originally looked like the Hobbits had hunted and butchered dwarf elephants—an impressive feat for such a tiny hominin. But according to University of Tübingen anthropologist Elizabeth Veatch and her colleagues, it was the Komodo dragons that were the hunters, while the Hobbits only showed up to scavenge what was left.

If Veatch and her colleagues are right, their findings may challenge some of the assumptions we’ve made about Homo floresiensis—and about which hominin species was the first to venture into the wider world beyond Africa.

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If I had a hammer... it might actually be a rhino tooth

2 June 2026 at 20:54

One way archaeologists learn how ancient people, including Neanderthals, did things is to attempt to do those things themselves, a process called experimental archaeology. Normally, that involves making stone tools, butchering deer, or distilling birch tar. But in a new study, it meant doing very destructive things to teeth from one of the world’s most carefully protected animals.

That's because the archeologists suspected that Neanderthals once used rhino teeth as tools. By using the teeth to make stone tools, the researchers demonstrated that Neanderthals probably did the same thing, adding to what we know about the wide range of items in their toolkits.

We need to hit some rhino teeth with rocks for science

Some Neanderthal archaeological sites in Europe and Asia seem to have many more rhinoceros teeth lying around than you’d expect. We know Neanderthals hunted a now-extinct species of rhinoceros in Europe and eastern Asia, but the people who had inhabited these sites looked like they had been collecting rhino teeth for some reason.

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© By Bernard DUPONT from FRANCE - White Rhino Skull, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=55453022

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