The role of megafaunal exploitation in early human evolution remains debated. Occasional use of large carcasses by early hominins has been considered by some as opportunistic, possibly a fallback dietary strategy, and for others a more important survival strategy. At Olduvai Gorge, evidence for megafaunal butchery is scarce in the Oldowan of Bed I but becomes more frequent and widespread after 1.8 Ma in Bed II, coinciding with the emergence of Acheulean technologies, but not functionally related to the main Acheulian tool types. Here, we present the earliest direct evidence of proboscidean butchery, including a newly documented elephant butchery site (EAK). This shift in behavior is accompanied by larger, more complex occupation sites, signaling a profound ecological and technological transformation. Rather than opportunistic scavenging, these findings suggest a strategic adaptation to megafaunal resources, with implications for early human subsistence and social organization. The ability to systematically exploit large prey represents a unique evolutionary trajectory, with no direct modern analogue, since modern foragers do so only episodically.

OBJECTIVES:Our study aimed to quantify the degrees of sexual dimorphism in facial shape and nineteen body parameters across eleven living populations from three major world regions: Sub-Saharan Africa (five populations), Europe (three populations), and Asia (three populations). METHODS:The data were collected in Tanzania and Russian Federation (N = 2214 individuals, aged 16-35 years), utilizing identical methods. Facial shape was explored through geometric morphometrics based on photographs. Body parameters were obtained through direct measurements. RESULTS:We found that body parameters are highly sexually dimorphic in humans and have population specificity: in taller and more robust populations (Europeans, Asians), body height, bone mass, handgrip strength, and wrist diameter are the most dimorphic traits, whereas Africans demonstrate the highest variability in body dimorphism. In contrast, the degree of facial sexual dimorphism increases from minimum in Africans to intermediate in Asians and maximum in European populations. Sexually dimorphic facial shape patterns vary by population origin, with allometry on average explaining over half of the sex differences. We did not find a linear relationship between overall degrees of body and facial dimorphism across study populations. However, dimorphism in several isolated body parameters correlated with facial dimorphism at the population level. Particularly, for body height, handgrip strength, and bone mass, such correlations remained evident even after correction for population phylogenetic relatedness. CONCLUSIONS:Differences in degrees of sexual dimorphism in study populations cannot be explained by allometry alone, but rather they result from a complex interplay of various factors and pressures, including phylogenetic origin, environmental conditions, and cultural norms.

ABSTRACT The study of the Eastern African archaeological record is essential for understanding the origin and evolution of the Middle Stone Age (MSA). However, Olduvai Gorge, one of the primary regions in human evolution studies, has few sites associated with the MSA. The zooarchaeological and taphonomic study of two MSA sites, Victoria Cabrera Site (VCS) and Dorothy Garrod Site (DGS), allows us to understand the dynamics of accumulation of faunal assemblages in the gorge. While VCS is the result of accumulation by water flows, DGS is the result of human activity, identified especially by bones burned by intentional fire action and by intentional fracturing for bone marrow extraction. The paleontological study has allowed us to compare the taxonomic abundance of the sites with current data from various ecosystems, along with analyses of stable carbon (δ 13 C) and oxygen (δ 18 O) isotopes and dental microwear analysis of tooth remains. We have verified that the dominant environment of Olduvai Gorge at this time was characterized by open C 4 savanna.

Olduvai Gorge (northern Tanzania) preserves a rich and continuous paleoanthropological record spanning the past two million years. While its Early Stone Age occupations have been intensively studied, the Middle and Later Stone Age sequences, represented by the Ndutu and Naisiusiu Beds, remain less understood. This study presents new geological and geochronological data from the type localities of the Ndutu and Naisiusiu Beds. Using optically stimulated luminescence (OSL), we establish a revised chronological framework for these sedimentary units. The Lower Ndutu Beds, composed of fluvially reworked conglomerates and sands capped by a trachytic tuff and silts, are now dated between 152.9 f 11.6 ka and 122.9 f 8.3 ka. The Upper Ndutu Beds include archaeologically rich sandy and silty facies and are dated between 86.9 f 4.5 ka and 70.8 f 10.4 ka. At the Naisiusiu type site, a sequence of fluvial, sheetwash, and aeolian deposits yielded OSL dates ranging from 65.3 f 4.4 ka to 32.8 f 2.2 ka, suggesting that the LSA occupation at Olduvai began significantly earlier than previously assumed. These results provide refined age estimates for the Middle and Later Stone Age deposits at Olduvai Gorge and confirm a relatively rapid transition between these two technocomplexes during the Late Pleistocene. The data strengthen regional correlations with sites like Nasera and Mumba, providing critical chronological resolution to ongoing debates about the tempo and mode of behavioural evolution in eastern Africa.

FLK West (Olduvai Gorge, Tanzania) is one of the earliest examples of the Acheulean complex in East Africa. It is a multi-component site, with significant patches of lithic tools and fossil bone preserved in the lowermost archaeo-units. Among the lithic collections, different fractions of the large tool operational sequences have been preserved (including large cores, large flakes, and LCTs). The sample related to these sequences and retrieved during the first stage of fieldwork in this site includes 75 specimens unearthed from the lowermost levels 5 and 6. This work focuses on the study of these specimens from two complementary perspectives: a comprehensive diacritical analysis procedure aimed at explaining LCT production and shaping strategies via the study of large core exploitation and large blank shaping sequences, and a techno-functional analysis of large flakes and LCTs following the standardized methodological principles of this analytical approach. By focusing on these two aspects, we will be able to provide a broad description of LCT production and shaping strategies and the goals undertaken by the Earliest Acheulean toolmakers at Olduvai Gorge. We will also generate a database of the functional potentiality of the resulting large tools, constituting a baseline for other experimental and macro use-wear analyses.

Understanding how host lifestyle and industrialization shape the human gut microbiome and intestinal physiology requires multimodal analyses across diverse global host contexts. Here, we generate multivariate data from the Global Microbiome Conservancy cohort, including gut microbiome, IgA-sequencing, host genotyping, diet, lifestyle and fecal biomarker profiles, to investigate host-microbiome interactions across gradients of industrialization and geography. We show that industrialization is associated with homogenized microbial compositions, reduced microbial diversity, and lower community stability, independent of host confounders. We further show that industrialization is linked to elevated markers of gut stress, increased IgA secretion, and altered patterns of IgA-bacteria interactions. Finally, we show that microbiome-based disease predictors trained on industrialized populations lose accuracy in less industrialized cohorts, highlighting limited cross-population transferability. Together, our results suggest profound restructuring of host-microbiome interactions due to industrialized lifestyles, and emphasize the need for inclusive, globally representative data to improve translational microbiome applications across diverse human populations.

Recent fieldwork at SHK Main site and SHK Extension (2009–2016) has recovered an abundant lithic sample that contains giant cores, large flakes and large cutting tools (LCT), such as bifaces, cleavers, picks and knives. Such a significant collection constitutes an opportunity to understand and reconstruct the chaîne opératoire of LCT production undertaken by hominins at this site complex. Through a technological approach based on detailed reconstructions of the large tool shaping patterns and the analysis of techno-functional potentiality, this work presents the study of lithic implements specifically related to the Acheulean sequence unearthed at SHK by our team. This assessment has been completed with other specimens identified by us among the original Leakey collections. The aim is to define the LCT conceptualization strategies of the SHK toolmakers. This information, in combination with subsequent experimental and use-wear analyses, will shed light on the functional meaning of the LCTs produced during the Early Acheulean.

Olduvai Gorge, nestled between the East African Rift Valley and the Mozambique Belt, is key to understanding human evolution. Even though extensive archaeological and palaeoanthropological findings have been unearthed here since the 1930s, the Middle Stone Age in this area has nonetheless received less attention than the Oldowan or the Acheulean. This paper presents the lithic technology analysis of Dorothy Garrod Site (DGS), a newly-documented MSA site located at the junction of the main gorge and the side gorge at Olduvai. DGS provides valuable additional knowledge to our understanding of the MSA groups that inhabited the region, offering insights into the mobility and settlement patterns of human groups in East Africa during MIS 4. This study focuses on the techno-typological characterization of the DGS lithic assemblage through an analysis of the raw material management strategies and knapping methods employed. The presence of discoid and Levallois methods, as well as single platform methods shows DGS to be a ‘typical’ MSA archaeological site, together with its associated fauna. The retouched pieces are scarce and characterized by a high presence of denticulates, retouched flakes and notches, as well as by the low presence of heavy-duty tools and total absence of points. All of these features make of DGS an exceptional MSA site at the heart of Olduvai.

Early and later hominins, including A. afarensis, P. aethiopicus and early Homo sapiens , occupied the Laetoli area in northern Tanzania from the Middle Pliocene through the Mid-Late Pleistocene (from 3.6 million to two hundred thousand years ago). After this period, there is a notable absence of evidence for human activity in the area. Recent investigations in the Laetoli highlands reveal material remains from the Later Stone Age ( LSA ) including stone tools, fauna, eggshells, ochre, and pottery. These cultural materials provide direct and reliable archaeological evidence of Late Pleistocene human occupation, demonstrating the ongoing nature of prehistoric human presence in Laetoli. Analysis of the culture-stratigraphic sequences and material associations between Laetoli and regional LSA deposits indicates human habitation during the Late Plaeistocene-African humid period into the middle Holocene.

The significance of the archaeological record unearthed in the SHK fluvial landscape represents a noteworthy dataset to study in greater detail the expression of inter-assemblage variability during the formally labelled Developed Oldowan/Acheulean interface in Olduvai Gorge. A precise stratigraphic interval, laterally continuous, and preserving fractions of anthropogenic activity at different points of the same fluvial network makes it feasible to identify the variable techno-economic ways in which hominins responded to the local paleo-landscape in a short time unit. In this work we present the results of the comparative techno-economic study of the three lithic collections retrieved from the time unit defined by an isochronous litho-stratigraphic volcanic horizon deposited in the fluvial landscape of SHK Main site and SHK Extension. The combined use of this isochrone plus the archaeo-stratigraphic method to refine time-averaging constraints offers for the first time an assessment of the nature of technological variation within different fractions of the same fluvial landscape at 1.5 Ma in Middle Bed II. The goal of this analysis is to look closely at inter-assemblage variability in a unit of time with a coherent degree of synchronicity and to add new data to the Developed Oldowan/Acheulean gradient.

We present the first published ethnographic description of landscape burning by Hadza hunter-gatherers of northern Tanzania and identify environmental, social, and cultural influences on Hadza landscape burning, thereby broadening the ethnographic record of anthropogenic burning practices described for hunter-gatherer communities. We report interview data collected in 2022 and 2023, describing their practices and attitudes regarding the causes and consequences of burning. We provide context by comparing our observations with those recorded for hunting and gathering populations in Africa, Australia, and North America. Hadza landscape burning is generally a solitary and male-dominated activity, contrary to ethnographic accounts of Indigenous landscape burning from North America and Australia. The primary goals stated by Hadza for landscape burning were improved hunting, reduced hazards from dangerous animals, and to reduce the density of livestock. Firsthand observations suggest that landscape burning has decreased over the past 20 years, and this historical trend is supported by interviews. Satellite imagery also suggests an overall decrease in burning activity in the region from 2001 to 2022. Among the Hadza, landscape burning is a culturally influenced and strongly gender-biased activity that is rapidly disappearing. Because burning can radically transform landscapes, these practices often generate or amplify conflicts of interest between groups with different land use strategies. Hadza report serious social conflict with pastoralists over landscape burning, and our study suggests this tension has constrained the practice in the past two decades.

The Mumba rockshelter, located in the northwest of Lake Eyasi is key to understanding the Stone Age in East Africa. The stratigraphy of the site spans the last 130 ka BP and comprises levels from the Middle Stone Age, the Later Stone Age, the Pastoral Neolithic, and the Iron Age. In terms of the Middle Stone Age (MSA), Mumba has helped to define two lithic industries: Sanzako (130 ka BP) and Kisele (90–50 Ka BP) that characterize this techno-complex in northern Tanzania. The Sanzako industry was defined based on level VI-B at Mumba, which was excavated in 1938 by Köhl-Larssen. Here we present the study of the lithic assemblage excavated by Mehlman between 1977 and 1981. Mehlman subdivided this unit into three sublevels (Lower, Middle, and Upper), all of which remained unanalyzed and therefore, unpublished. The main features of the lithic assemblages found in the three sublevels are the presence of discoid, Levallois, and bipolar knapping methods. Additionally, the retouched tools are mainly sidescrapers, denticulates, and notches. This recent research enables us to understand the Sanzako industry in more detail, as well as its nature within the chronocultural framework of the MSA in northern Tanzania.

Human evolutionary ecology stands to benefit by integrating theory and methods developed in movement ecology, and in turn, to make contributions to the broader field of movement ecology by leveraging our species' distinct attributes. In this paper, we review data and evolutionary models suggesting that major changes in socio-spatial behaviour accompanied the evolution of language. To illustrate and explore these issues, we present a comparison of GPS measures of the socio-spatial behaviour of Hadza hunter-gatherers of northern Tanzania to those of olive baboons (Papio anubis), a comparatively small-brained primate that is also savanna-adapted. While standard spatial metrics show modest differences, measures of spatial diversity, landscape exploration and spatiotemporal displacement between individuals differ markedly. Groups of Hadza foragers rapidly accumulate a vast, diverse knowledge pool about places and things over the horizon, contrasting with the baboon's narrower and more homogeneous pool of ecological information. The larger and more complex socio-spatial world illustrated by the Hadza is one where heightened cognitive abilities for spatial and episodic memory, navigation, perspective taking and communication about things beyond the here and now all have clear value.This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

In this experimental study, we continue investigating an association between facial morphology and individual psychological characteristics. The study was conducted in the population of Maasai (Ngorongoro, Tanzania) in two stages during field trips in 2016 and 2021. At the first stage, we collected anthropological photo portraits from 305 individuals (123 women and 182 men) and interviewed them to identify the propensity to help others. Six generalized morphed portraits of Maasai (men and women) were created based on individual propensity to help. At the second stage of the study, portraits were presented to 200 Maasai, men and women from the same population. The portraits were evaluated according to the degree of expression of four qualities: physical strength, proneness to help others, a "good friend", and self-confidence. The results of the study revealed that representatives of the same population are able to distinguish altruistic men by their facial shape. Men who were prone to provide assistance to others were perceived as physically stronger. No such association was found for female portraits. The results are interpreted from the standpoint of evolutionary psychology.