Eocene Primate Fossil Alters Evolutionary Tree

A field crew collects fossils along the Smiley Draw sandstone in Wyoming.
Photo Credit: Robert Anemone

Scientific Frontline: Extended "At a Glance" Summary: Tetonius varleyorum and Early Primate Evolution

The Core Concept: Tetonius varleyorum is a newly identified, mouse-lemur-sized species of extinct omomyid primate that challenges the previously accepted step-by-step evolutionary model of early mammals.

Key Distinction/Mechanism: Past models, based heavily on localized fossils from the Bighorn Basin, suggested a single, unbranching evolutionary line (anagenesis) for the genus Tetonius; however, fossils from the new Wyoming locale prove a more complex pattern of branching speciation.

Origin/History: Dating back roughly 55 million years to the warm Eocene epoch, the fossils were collected at the Smiley Draw site in Wyoming. The findings were published in the Journal of Human Evolution by researchers from the University of Kansas and the University of North Carolina at Greensboro.

Major Frameworks/Components:

• Omomyidae Family Tree: Extinct, early "true primates" that represent a crucial branching point near the common ancestors of modern lemurs, monkeys, apes, and humans.
• Biogeographical Sampling: The crucial role of expanding fossil recovery beyond well-documented basins to prevent skewed interpretations of evolutionary history.
• Anagenesis vs. Cladogenesis: The shift from viewing evolutionary transitions as a straight, non-branching progression to recognizing complex, branching speciation events in the fossil record.

Archaic Human Infants Were Helpless

An artist’s reconstruction of how Homo erectus parents cared for their children.
Based on this research, the team believes Homo erectus mothers held helpless newborns in their arms and shared caregiving duties with the father and other group members. Laying newborns with immature head and neck muscles on the ground can cause deformational plagiocephaly.
Illustration Credit: Utako Kikutani. ©Yousuke Kaifu
(CC BY 4.0)

Scientific Frontline: Extended "At a Glance" Summary: Helpless Infancy in Archaic Humans

The Core Concept: A recent morphological study of fossilized skulls reveals that archaic humans, including Homo erectus and Homo floresiensis, birthed physically helpless infants that required intensive, constant parental care similar to modern human babies.

Key Distinction/Mechanism: Unlike other great apes that are born physically capable and exhibit a narrow range of cranial deformity, archaic human infants lacked neck muscle strength and had soft cranial bones. Because they were laid down frequently without the ability to lift or turn their heads, their skulls developed deformational plagiocephaly (flat head syndrome), leaving a permanent structural signature of helplessness.

Major Frameworks/Components:

• Deformational Plagiocephaly Analysis: Identifying non-disease, post-birth structural skewness in adult fossils to infer infant immobility and underdeveloped musculature.
• Comparative Morphology: Measuring and comparing head shapes across 123 modern infants, 385 historical human skulls, 996 great ape skulls, and fossilized specimens of early Homo species.
• The Obstetrical Dilemma: Investigating the evolutionary trade-off between bipedalism, which restricts the size of the birth canal, and the necessity of birthing neurologically immature offspring to accommodate future brain development.

Fossil Footprints Reveal Hominin Behavior

One of the large, 1.4-million-year-old footprints that the team excavated. A 6-inch (~15 cm) ruler is shown for scale.
Photo Credit: © Kay Behrensmeyer

Scientific Frontline: Extended "At a Glance" Summary: Paranthropus boisei Fossil Footprints

The Core Concept: The discovery of 1.4-million-year-old fossil footprints in northern Kenya preserves the tracks of eight Paranthropus boisei individuals, providing direct evidence of their anatomy, locomotion, and behavior.

Key Distinction/Mechanism: Unlike isolated fossil bones that previously led to underestimates of physical dimensions, these trace fossils reveal that Paranthropus boisei reached human-like body sizes (up to 1.8 meters tall and 75 kilograms) and possessed a complex social structure involving group travel by adult males.

Origin/History: The footprints date to approximately 1.4 million years ago during the Early Pleistocene and were discovered in the East Turkana region of northern Kenya, with the analytical methods used to identify them pioneered in 2024.

Major Frameworks/Components:

• Morphometric analysis of foot anatomy and movement patterns indicating larger-than-expected physical sizes.
• Behavioral interpretation of trackways suggesting cohesive, male-dominated group travel and social tolerance.
• Geological and paleoenvironmental assessments demonstrating the sustained utilization of lake margin habitats by hominins over 100,000 years.

Human and Neanderthal Shared Culture

A distant view of the Üçağızlı II Cave in southern Türkiye.
Photo Credit: KyotoU / Naoki Morimoto

Scientific Frontline: Extended "At a Glance" Summary: Human and Neanderthal Cultural Continuity

The Core Concept: Recent archaeological evidence indicates that modern humans (Homo sapiens) and Neanderthals (Homo neanderthalensis) shared a continuous culture spanning over 20,000 years, engaging in deep behavioral and technological exchange.

Key Distinction/Mechanism: Unlike previous models that emphasized simple spatial coexistence or genetic introgression, these findings demonstrate that the two distinct species shared complex, non-utilitarian behaviors, such as the selective collection of symbolic marine seashells that were previously attributed exclusively to modern humans.

Major Frameworks/Components:

• Technological Parity: The utilization of identical stone tool technologies and survival strategies by both species occupying the same geographic space.
• Symbolic Material Culture: A mutual preference for collecting specific marine seashells with no nutritional value, indicating shared symbolic preferences and cultural transmission across the biological divide.
• Migration Corridors: The site's location in the Levant highlights a critical evolutionary crossroads, capturing individuals who may represent the founding lineage of all living non-African populations.

Neanderthal Genetics Challenge Extinction Theories

A lifelike museum reconstruction of a Neanderthal hunter crouching outdoors among rocks and fallen leaves, using a stone tool to process a small animal carcass. He wears animal fur and has long dark hair and a facial marking.
Photo Credit: Pressebilder Neanderthal Museum, Mettmann/Wikimedia Commons

Scientific Frontline: Extended "At a Glance" Summary: Late Neanderthal Population Genetics

The Core Concept: A recent genetic analysis of late Neanderthals (Homo neanderthalensis) in Western Europe indicates that these populations were genetically diverse, healthy, and interconnected just before their extinction.

Key Distinction/Mechanism: Unlike earlier Neanderthal populations that showed severe signs of inbreeding, individuals from the Meuse Basin around 45,000 years ago displayed no evidence of "inbreeding depression" or genetic mixing with anatomically modern humans (Homo sapiens).

Origin/History: Neanderthals survived across Eurasia for hundreds of thousands of years before vanishing approximately 40,000 years ago. This study analyzed ancient DNA extracted from the bones of 27 individuals who lived between 49,000 and 40,000 years ago in present-day Belgium and France.

Major Frameworks/Components:

• Genetic Diversity Analysis: Researchers examined stretches of DNA for identical base pairs to detect inbreeding, which can compromise a population's adaptability, disease resistance, and fertility.
• Lineage Tracking: Mitochondrial DNA revealed a common maternal lineage coexisting with a distinct alternative lineage, while Y-chromosome data indicated diverse paternal ancestry among the males.
• Kinship Limitations: Advanced computational methods established that the sampled individuals shared no closer than third-degree relatedness (approximately 12.5% shared DNA), a level comparable to first cousins.

Nature Exposure Boosts Physical Endurance

Photo Credit: Aurelien Thomas

Scientific Frontline: Extended "At a Glance" Summary: Nature Exposure and Physical Endurance

The Core Concept: Exposure to natural environments prior to exercise increases physical endurance by 7.5% compared to time spent in urban industrialized settings.

Key Distinction/Mechanism: The performance enhancement occurs without changes in cardiovascular output or oxygen uptake. Instead, the mechanism relies on psychological improvements (heightened mood and optimism) and the absence of urban physiological stressors (noise, artificial light, pollution), augmented by exposure to biological supporters like tree-emitted phytoncides.

Origin/History: The research is anchored in the Environmental Mismatch Hypothesis, which posits that rapid global industrialization over the past 200–300 years has drastically outpaced human evolutionary adaptation, leaving modern humans physiologically ill-suited to urban habitats.

Major Frameworks/Components:

• Environmental Mismatch Hypothesis: The evolutionary framework stating that human physiology is optimized for ancestral natural habitats rather than modern industrialized environments.
• Psychological Mediation: Performance benefits are partially driven by positive acute shifts in cognitive and emotional states, specifically prolonged improvements in mood and optimism.
• Stressor Reduction: The removal of modern environmental strains, including air pollution and artificial stimuli, which actively drain physiological capacity.
• Biochemical Interaction: The potential metabolic and physiological support provided by airborne organic compounds, such as phytoncides, naturally released by trees.

Environmental Stewardship in Conservation

Photo Credits: Tim Bruijninckx – VSF-B

Scientific Frontline: Extended "At a Glance" Summary: Environmental Stewardship in Biodiversity Conservation

The Core Concept: Environmental stewardship encompasses the reciprocal relationships, intentional practices, and ancestral knowledge of Indigenous and local communities used to manage and protect the natural environment. Integrating these practices into scientific and political frameworks aims to achieve more inclusive, socially just, and effective nature conservation.

Key Distinction/Mechanism: Unlike conventional, top-down conservation models that often exclude human activity or focus strictly on isolated taxa, this approach views biophysical management as inextricably linked to spiritual, social, and political dimensions. It relies on the mutual care and intentional management between human communities and "key cultural species" within a broader socio-ecological system.

Origin/History: A comprehensive global framework for this approach was recently presented by researchers at the University of Barcelona (led by Giulia Mattalia and Irene Teixidor). By reviewing hundreds of scientific articles, the team cataloged traditional management practices targeting nearly 1,000 culturally significant species worldwide, marking the first global-scale review of its kind.

Early African Herder Diets & Climate Adaptation

People buried at Gishimangeda Cave near Lake Eyasi (pictured) in Tanzania provided evidence of later herders’ more specialized diets.
Photo Credit Mary Prendergast

Scientific Frontline: Extended "At a Glance" Summary: Early Pastoralist Dietary Diversity

The Core Concept: Analysis of ancient remains reveals that the earliest livestock herders in eastern Africa did not immediately adopt a specialized pastoral diet but maintained highly diverse, individualized diets consisting of fish, wild game, and foraged plants alongside domesticated animals for over a millennium.

Key Distinction/Mechanism: Instead of relying solely on domesticated cattle, sheep, and goats, early pastoralists utilized a mixed-subsistence strategy to mitigate the risks of climate instability. Researchers identified this by analyzing stable isotopes in ancient human teeth—which provide a long-term dietary record—coupled with the extraction of fatty residues preserved in ancient ceramic cooking pots.

Origin/History: This dietary flexibility was observed in early herding populations living around Lake Turkana approximately 5,000 years ago. The broader study analyzed human remains in Kenya and Tanzania spanning a timeline from 9,500 to 200 years ago, highlighting a delayed transition to a purely livestock-centered diet.

Stone age population collapse revealed by DNA study in France

The researchers have conducted DNA analyses of the skeletons from a burial sites in France and found traces of several different diseases.
Image Credit: Scientific Frontline

Scientific Frontline: Extended "At a Glance" Summary: Stone Age Population Collapse and Turnover in France

The Core Concept: Genetic analyses of ancient skeletons from a megalithic tomb in France reveal a dramatic population collapse during the "Neolithic decline" around 3000 BC, which was subsequently followed by the immigration and genetic replacement by a distinct population from southern Europe.

Key Distinction/Mechanism: Unlike traditional models that often trace demographic shifts through artifacts alone, this study utilizes whole-genome DNA sequencing to prove a complete genetic break between two chronological groups at the same site. It demonstrates that the decline was driven by a complex matrix of diseases and environmental stress, rather than a single pathogen, resulting in a total replacement of the local population rather than genetic continuity.

Origin/History: The research centers on a large megalithic tomb near Bury, France, used between 3200 and 2450 BC. Genetic analyses of 132 individuals revealed that the population collapse and subsequent turnover occurred around 3000 BC, a period corresponding with the broader European "Neolithic decline."

Plague outbreaks in the Early Modern period hit working youths the hardest

During excavations beneath Basel’s Stadtcasino, several graves were uncovered. Multiple skeletons were found stacked on top of each other within the burial pits.
Photo Credit: Archäologische Bodenforschung Basel-Stadt, Adiran Jost

Scientific Frontline: Extended "At a Glance" Summary: Socioeconomic Vulnerability in Early Modern Plague Outbreaks

The Core Concept: Archaeoanthropological research demonstrates that working youths from lower socioeconomic backgrounds experienced the highest vulnerability and mortality rates during the last Early Modern plague epidemic in Basel, Switzerland.

Key Distinction/Mechanism: Contrary to the historical assumption that the plague killed indiscriminately, this research establishes that individuals forced to perform physically demanding labor for survival could not isolate, thereby disproportionately increasing their risk of both infection and death compared to wealthier classes.

Major Frameworks/Components: 

• Archaeoanthropology: The analysis of human skeletal remains to identify physical markers of arduous labor and subsequent health outcomes among adolescents.
• Epidemiological Sociology: The examination of how socioeconomic status, citizenship, and social capital directly influenced disease vulnerability and access to community support networks.
• Historical Demography: The synthesis of archaeological findings with primary sources from the Basel State Archives to reconstruct public health dynamics and mortality in the Early Modern period.

Tracking the footsteps of West Africa's prehistoric metalworkers

Photograph taken during the discovery of a pile of used tuyères, featuring intriguing transverse perforations, for photogrammetry purposes.
Photo Credit: © Anne Mayor

Scientific Frontline: Extended "At a Glance" Summary: Prehistoric West African Iron Metallurgy

The Core Concept: An exceptionally well-preserved iron-smelting workshop located in eastern Senegal provides detailed evidence of sub-Saharan African iron production dating back 2,400 years.

Key Distinction/Mechanism: Unlike typical metallurgical sites that are abandoned after a few generations, this workshop remained operational and remarkably stable for nearly eight centuries. The site operated using a specialized technique where large clay "tuyères" (air pipes) featured multiple perpendicular side ducts rather than a single outlet, allowing for highly optimized air distribution to the bottom of the furnace.

Major Frameworks/Components:

• FAL02 Metallurgical Tradition: A distinct iron-ore smelting practice utilizing small circular bloomery furnaces (approximately 30 cm deep) topped with removable chimneys.
• Advanced Tuyère System: Semicircular arrangements of engineered clay pipes designed with complex side openings to channel and distribute air efficiently during the smelting process.
• Novel Packing Materials: The previously undocumented use of palm nut seeds as foundational packing material at the base of the smelting furnaces.

Ancient DNA reveals 12,000-year-old case of rare genetic disease

Daniel Fernandes preparing to take a sample
Photo Credit: ©Adrian Daly

Scientific Frontline: Extended "At a Glance" Summary

The Core Concept: Researchers have successfully performed the earliest known genetic diagnosis in humans, identifying a rare inherited growth disorder called acromesomelic dysplasia in a 12,000-year-old skeleton found in Italy.

Key Distinction/Mechanism: While traditional archaeology often relies on skeletal measurements to infer health conditions, this study utilized ancient DNA (aDNA) sequencing to pinpoint specific mutations. By extracting DNA from the petrous part of the temporal bone, scientists identified a homozygous mutation in the NPR2 gene responsible for the severe short stature in the daughter, and a heterozygous mutation in the mother, which caused a milder form of the condition.

Origin/History: The skeletal remains were originally excavated in 1963 at the Grotta del Romito in southern Italy and date back to the Upper Paleolithic period (over 12,000 years ago).

Major Frameworks/Components:

• Ancient DNA (aDNA) Analysis: Extraction and sequencing of genetic material from prehistoric bone samples.
• Targeted Gene Screening: Focusing specifically on genes known to influence skeletal growth, such as NPR2.
• Comparative Clinical Genetics: Cross-referencing ancient genetic variants with modern medical databases to confirm diagnoses.

Branch of Science: Paleogenomics, Clinical Genetics, Evolutionary Anthropology, and Physical Anthropology.

Future Application: This methodology paves the way for reconstructing the medical history of ancient populations, diagnosing other rare diseases in the archaeological record, and understanding the evolutionary timeline of specific genetic mutations.

Why It Matters: This discovery proves that rare genetic diseases are not exclusively modern phenomena but have persisted throughout human history. Furthermore, the survival of the severely disabled individual into adulthood provides profound evidence of social care and community support in prehistoric hunter-gatherer societies.

Mineralized dental plaque from the Iron Age provides insight into the diet of the Scythians

A Scythian. Found in the kurgan Olon-Kurin-Gol 10, Altai Mountains, Mongolia.
Image Credit: reconstruction by Dimitri Pozdniako
(Wikimedia CC 4.0)

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Analysis of mineralized dental plaque from the Iron Age provides the first direct biomolecular evidence that Scythian populations consumed milk from various ruminants and horses.
• Methodology: Researchers performed paleoproteomic analysis on dental calculus samples collected from 28 individuals excavated at the Bilsk and Mamai-Gora archaeological sites in modern-day Ukraine to identify preserved dietary proteins.
• Key Data: Specific milk proteins from cattle, sheep, or goats were identified in six individuals, while horse milk proteins were detected in a single sample, physically validating ancient textual references to mare's milk consumption.
• Significance: The findings challenge the traditional simplified narrative of Scythians as uniform nomadic warriors, supporting a more nuanced model of a multi-ethnic society with diverse subsistence strategies including pastoralism and local sedentarism.
• Future Application: This proteomic methodology will be scaled to analyze larger cohorts across the Eurasian steppe to map regional dietary variations, social stratifications, and temporal changes in Iron Age food systems.
• Branch of Science: Bioarchaeology and Paleoproteomics
• Additional Detail: The isolation of horse milk proteins in only one individual raises questions about potential social hierarchies, suggesting that consumption of specific dairy products may have been restricted or culturally significant.

Hygienic conditions in Pompeii’s early baths were poor

Pools of the oldest public bathing facilities in Pompeii, dating back to 130 BC
Photo Credit:© Cees Passchier

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Isotope analysis of carbonate deposits reveals that Pompeii’s early "Republican Baths" (c. 130 BC) maintained poor hygienic conditions, relying on stagnant, highly mineralized well water rather than fresh aqueduct supplies.
• Methodology: Researchers reconstructed the ancient water supply by analyzing stable isotopes and trace elements in limescale (calcium carbonate) samples collected from the city’s wells, water towers, and bath pools.
• Key Data: Anthropogenic deposits contained distinct peaks of lead, zinc, and copper, indicating significant heavy metal contamination caused by the corrosion of the facility's boilers and pipes.
• Mechanism: Prior to the Augustan aqueduct, water was extracted via slave-powered treadwheels; this labor-intensive process limited water renewal to roughly once per day, failing to flush contaminants effectively.
• Significance: The findings challenge the historical assumption of uniformly high Roman hygiene, demonstrating that superior sanitation standards were only achievable after the introduction of high-volume aqueduct infrastructure.
• Volcanic Insight: Cyclic patterns observed in the carbon isotopes of well deposits suggest fluctuating volcanic CO₂ levels, potentially serving as a paleo-record of Mount Vesuvius's activity prior to the AD 79 eruption.

First ancient human herpesvirus genomes document their deep history with humans

Laboratory technician and one of the authors in the contamination-controlled ancient DNA laboratory at the University of Tartu extracting tiny amounts of DNA from centuries-old skeletons.
Photo Credit: Courtesy of University of Tartu

For the first time, scientists have reconstructed ancient genomes of Human betaherpesvirus 6A and 6B (HHV-6A/B) from archaeological human remains more than two millennia old. The study, led by the University of Vienna and University of Tartu (Estonia) and published in Science Advances, confirms that these viruses have been evolving with and within humans since at least the Iron Age. The findings trace the long history of HHV-6 integration into human chromosomes and suggest that HHV-6A lost this ability early on. 

HHV-6B infects about 90 percent of children by the age of two and is best known as the cause of roseola infantum – or "sixth disease" – the leading cause of febrile seizures in young children. Together with its close relative HHV-6A, it belongs to a group of widespread human herpesviruses that typically establish lifelong, latent infections after an initial mild illness in early childhood. What makes them exceptional is their ability to integrate into human chromosomes – a feature that allows the virus to remain dormant and, in rare cases, to be inherited as part of the host's own genome. Such inherited viral copies occur in roughly one percent of people today. While earlier studies had hypothesized that these integrations were ancient, the new data from this study provide the first direct genomic proof. 

Farmers boosted Europe's biodiversity over the last 12,000 years

Standing stones in Carnac, France. Built between 6,500 - 5,300 years ago by Europe's first farmers.
 Photo Credit: Jonny Gordon.

Although humans are to blame for nature’s recent decline, a new study shows that for millennia, European farming practices drove biodiversity gains, not losses. 

Standing stones in Carnac, France. Built between 6,500 - 5,300 years ago by Europe's first farmers. Picture by Jonny Gordon. 

A team of researchers at the University of York analyzed fossil pollen records from Europe to track vegetation changes stretching back 12,000 years. They discovered that as new populations of farmers from Turkey moved into Europe 9,000 years ago, far from destroying plant diversity, they enriched it. 

Dr Jonny Gordon is a Postdoctoral Research Associate in the Leverhulme Centre for Anthropocene Biodiversity and lead author of the new paper, Increased Holocene diversity in Europe linked to human-associated vegetation change, which has been published in Global Ecology and Biogeography. 

Australopithecus deyiremeda, an ancestor of the human species discovered in Ethiopia, was bipedal and climbed trees

Professor Lluís Gibert, from the University of Barcelona, is the only expert from a European institution participating in an international study based on the analysis of the bones of a fossilized foot and teeth that has revealed how Australopithecus deyiremeda, a human ancestor that coexisted more than three million years ago with Australopithecus afarensis — the famous Lucy — on the plains of East Africa, moved and fed.
Photo Credit: Courtesy of University of Barcelona

In 2009, scientists found eight bones from the foot of a human ancestor in layers of ancient sediment at the Woranso-Mille site in the central Afar region of Ethiopia. The fossil remains, known as the Burtele Foot, were discovered by a team led by paleoanthropologist Yohannes Haile-Selassie, from Arizona State University (United States), but were not assigned to any fossil species of a human ancestor from the African continent.

A study now published in the journal Nature and led by Haile-Selassie solves the mystery and reveals that Burtele Foot belongs to the species Australopithecus deyiremeda, a new hominid fossil discovered years ago by the researcher’s team at the Woranso-Mille site (Nature, 2015). Thus, the study of this fossil foot — dated to about 3.4 million years ago — reveals that A. deyiremeda was an Australopithecus that walked on two limbs (bipedalism) and also lived in trees, as indicated by the presence of a prehensile big toe like that of chimpanzees. 

The international team of experts includes Professor Lluís Gibert, from the Faculty of Earth Sciences of the University of Barcelona, who is the only researcher from a European institution to sign the study. Geological analyses were decisive for dating and linking this foot to the remains of A. deyiremeda. 

Anthropology: In-Depth Description

Easter Island, a Chilean territory, is a remote volcanic island in Polynesia. Its native name is Rapa Nui. It’s famed for archaeological sites, including nearly 900 monumental statues called moai, created by inhabitants during the 13th–16th centuries. The moai are carved human figures with oversize heads, often resting on massive stone pedestals called ahus. Ahu Tongariki has the largest group of upright moai.
Photo Credit: Sofia Cristina Córdova Valladares

Anthropology (Social Science) is the holistic and comparative study of humanity. It seeks to understand every aspect of the human condition—our origins, development, and diversity—across all of in time and space.

The discipline's primary goal is to answer the question: "What does it mean to be human?" To do this, it synthesizes knowledge from social sciences, natural sciences, and the humanities, examining our biology, culture, language, and history collectively.

What Is: Extinction Level Events

A Chronicle of Earth's Biotic Crises and an Assessment of Future Threats
Image Credit: Scientific Frontline

Defining Biotic Catastrophe

The history of life on Earth is a story of breathtaking diversification and innovation, but it is punctuated by chapters of profound crisis. These are the extinction level events—catastrophes of such magnitude that they fundamentally reset the planet's biological clock. Popular imagination often pictures a single, sudden event, like the asteroid that sealed the fate of the dinosaurs. The geological reality, however, is more complex and, in many ways, more instructive for our current era. Understanding these events requires a rigorous scientific framework that moves beyond simple notions of species loss to appreciate the systemic collapse of entire global ecosystems.

Did Lead Limit Brain and Language Development in Neanderthals and Other Extinct Hominids?

UC San Diego researchers have found high levels of lead in the teeth of both Neanderthals (left) and modern humans (right). However, a gene mutation may have protected modern human brains, allowing language to flourish.
Photo Credit: Kyle Dykes/UC San Diego Health Sciences

Ancient human relatives were exposed to lead up to two million years ago, according to a new study. However, a gene mutation may have protected modern human brains, allowing language to flourish.

What set the modern human brain apart from our now extinct relatives like Neanderthals? A new study by University of California San Diego School of Medicine and an international team of researchers reveals that ancient hominids — including early humans and great apes — were exposed to lead earlier than previously thought, up to two million years before modern humans began mining the metal. This exposure may have shaped the evolution of hominid brains, limiting language and social development in all but modern humans due to a protective genetic variant that only we carry. The study was published in Science Advances.

The researchers analyzed fossilized teeth from 51 hominids across Africa, Asia and Europe, including modern and archaic humans such as Neanderthals, ancient human ancestors like Australopithecus africanus, and extinct great apes such as Gigantopithecus blacki.