Millennial Ambition
Major expansion in the human niche preceded out of Africa dispersal
Emily Hallett et al.
Nature, forthcoming
Abstract:
All contemporary Eurasians trace most of their ancestry to a small population that dispersed out of Africa about 50,000 years ago (ka). By contrast, fossil evidence attests to earlier migrations out of Africa. These lines of evidence can only be reconciled if early dispersals made little to no genetic contribution to the later, major wave. A key question therefore concerns what factors facilitated the successful later dispersal that led to long-term settlement beyond Africa. Here we show that a notable expansion in human niche breadth within Africa precedes this later dispersal. We assembled a pan-African database of chronometrically dated archaeological sites and used species distribution models (SDMs) to quantify changes in the bioclimatic niche over the past 120,000 years. We found that the human niche began to expand substantially from 70 ka and that this expansion was driven by humans increasing their use of diverse habitat types, from forests to arid deserts. Thus, humans dispersing out of Africa after 50 ka were equipped with a distinctive ecological flexibility among hominins as they encountered climatically challenging habitats, providing a key mechanism for their adaptive success.
An empirically-based scenario for the evolution of cultural transmission in the human lineage during the last 3.3 million years
Ivan Colagè & Francesco d’Errico
PLoS ONE, June 2025
Abstract:
Humans accumulate an ever-growing body of knowledge that far exceeds the capacity of any single individual or generation. Social learning and transmission are essential for this process. However, how cultural transmission strategies evolved in our lineage remains unclear. Here we assess the transmission strategies needed to ensure the perpetuation across generations of 103 cultural traits that emerged in the Paleolithic. Our study provides a novel approach to assessing the transmission behaviors implicated in Paleolithic cultural traits and the evolution of cultural transmission over the last 3.3 million years. The results identify trends in the evolution of cultural transmission and reveal a coevolutionary dynamic between the emergence of novel cultural traits and the complexification of transmission strategies. While effective means of overt explanation, perhaps associating gesture and verbal expression, were already present at least 600,000 years ago, the period between 200,000 and 100,000 years ago appears as a crucial tipping point for the emergence of modern language.
Droughts and conflicts during the late Roman period
Charles Norman et al.
Climatic Change, April 2025
Abstract:
Despite continuous investigation, reasons for both the abandonment of Roman Britain around 410 CE, and the separate collapse of the Western Roman Empire in 476 CE remain unclear. Here, we use tree ring-based climate reconstructions and written documentary sources to show that a sequence of severe summer droughts from 364 to 366 CE not only contributed to prolonged harvest failures and food shortages, but also played a role in the ‘Barbarian Conspiracy’, a catastrophic military defeat for Roman Britain in 367 CE. In line with contemporary reports from the historian Ammianus Marcellinus, this pivotal event in pre-modern history coincided with anomalous coin hoarding, and a gradual depopulation of Roman villas and towns. Expanding our climate-conflict analysis from Roman Britain as a case study to the entire Roman Empire and the period 350–476 CE reveals clear linkages between years in which battles occurred and preceding warm and dry summers. Based on these findings, we develop a mechanistic model to explain the vulnerability of agrarian societies to climate variability, whereby prolonged droughts cause harvest failures and food shortages (dependent on societal resilience) that lead to systematic pressure, societal instability, and eventually outright conflict.
Macroevolutionary analysis of polysynthesis shows that language complexity is more likely to evolve in small, isolated populations
Lindell Bromham et al.
Proceedings of the National Academy of Sciences, 17 June 2025
Abstract:
Evolution of complexity in human languages has been vigorously debated, including the proposal that complexity can build in small, isolated populations but is often lost in situations of language contact. If it is generally true that small, isolated languages can build morphological complexity over time, but complexity tends to be lost in situations of language contact, then we should find that forms of language complexity that have evolved multiple times will tend to be associated with population size, isolation, and language age. We test this hypothesis by focusing on one particular form of morphological complexity, polysynthesis, where words built from many parts embody complex phrases. By assembling a global database of polysynthetic languages and conducting phylospatial analyses, we show that languages with highly complex word morphology are more likely to have small population sizes, less likely to occur with many other languages in direct contact, and have a greater tendency to be on long phylogenetically isolated lineages. These findings are consistent with the hypothesis that languages that evolve in isolation for long periods may be more likely to accrue morphological complexity. Polysynthetic languages also tend to have higher levels of endangerment. Our results provide phylogenetically informed evidence that one particular form of complex language morphology is more likely to occur in small, isolated languages and is prone to loss in contact.
Agent-based simulations reveal the possibility of multiple rapid northern routes for the second Neanderthal dispersal from Western to Eastern Eurasia
Emily Coco & Radu Iovita
PLoS ONE, June 2025
Abstract:
Genetic and archaeological evidence imply a second major movement of Neanderthals from Western to Central and Eastern Eurasia sometime in the Late Pleistocene. The genetic data suggest a date of 120−80 ka for the dispersal and the archaeological record provides an earliest date of arrival in the Altai by ca. 60 ka. Because the number of archaeological sites linking the two regions is very small, the exact route taken and its timing have been the matter of considerable debate. In particular, climate change in this period modified landscapes considerably, changing the cost of moving in different directions. Here, we apply agent-based least-cost path simulations for the first time to Neanderthals, showing that they most likely took a northern route through the Urals and southern Siberia under all climate scenarios. Agents leaving either the southern or the northern Caucasus Mountains reach the Altai in less than 2000 years during two time windows when the climate was mild, in MIS 5e (the Last Interglacial) and in MIS 3. The latter coincides with the dated presence of Neanderthals at Chagyrskaya and Okladnikov Caves in the Altai. The results of this modeling approach demonstrate a remarkable east-west geographic connectivity of northern Eurasia via river corridors despite the presumed barriers of the Ural Mountains and major north-south flowing rivers. Our results highlight the unique strengths of agent-based simulations to reconstruct pathways for ancient migrations.
Early evidence for pig domestication (8,000 cal. BP) in the Lower Yangtze, South China
Jiajing Wang et al.
Proceedings of the National Academy of Sciences, 17 June 2025
Abstract:
The domestication of pigs (Sus scrofa) has had profound socioeconomic and ecological consequences. Although pigs are believed to have been independently domesticated in South China, the timing and initial mechanisms of this process remain debated. This study presents a microfossil analysis of pig dental calculus from two early Neolithic sites in the Lower Yangtze River region: Jingtoushan (8,300 to 7,800 cal. BP) and Kuahuqiao (8,200 to 7,000 cal. BP). Analyses of starch, phytolith, and parasite remains indicate that pigs consumed human-associated foods and waste, including cooked starchy plants and human whipworm (Trichuris trichiura) eggs, likely derived from food preparation and fecally contaminated materials. Identified plant taxa include acorns (Fagaceae), rice (Oryza sp.), underground storage organs such as yam (Dioscorea sp.), and wild grasses (Triticeae and Panicoideae), all present in the local botanical assemblages. Coefficients of variation in dental metrics further indicate the coexistence of both domestic and wild populations. Together, these lines of evidence point to multiple modes of human–pig interaction, including early domestic pigs under human management, pigs scavenging near settlements, and free-ranging individuals foraging beyond human influence. Pig domestication in the Lower Yangtze had begun by 8,000 y ago, likely following both commensal and prey pathways, in parallel with the development of rice cultivation and sedentary lifeways. This study also demonstrates the value of dental calculus analysis for revealing early human–animal relationships before the appearance of clear morphological markers of domestication in the archaeological record.
The proteome of the late Middle Pleistocene Harbin individual
Qiaomei Fu et al.
Science, forthcoming
Abstract:
Denisovans are a hominin group primarily known through genomes or proteins, but the precise morphological features of Denisovans remain elusive due to the fragmentary nature of discovered fossils. Here we report ninety-five endogenous proteins retrieved from a nearly complete cranium from Harbin, China, dating to at least 146,000 years ago and previously assigned to a new species, Homo longi. This individual has three Denisovan derived amino acid variants and clusters with Denisova 3, suggesting the Harbin individual belongs to a Denisovan population. This study fills the gap between morphological and molecular evidence, enhancing our understanding of Denisovans’ spatiotemporal dispersal and evolutionary history.