Uncovering the evolution of Edo-period Japanese ceramic jars

  

Caption

AI-assisted shape analysis of Edo-period Ogame jars reveals how ceramic production became increasingly standardized while adapting to different every day and burial functions as well as key historical events.

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Institute of Science Tokyo

Edo-period “Ogame” (“large jars”) became increasingly standardized over time, developing distinct shapes for everyday and burial use, reports a new archeological study from Institute of Science Tokyo, Japan. Using AI-assisted techniques and geometric morphometrics, the researcher analyzed 243 historic vessels to quantitatively track these changes. The findings provide the first quantitative evidence that major Edo-period historical events influenced not only expensive porcelains production but also everyday ceramics, offering new insights into early modern Japanese society.

Archeological artifacts offer valuable insights into the history of past societies. These reveal not only technological developments but also the changing economic systems, cultural traditions, and everyday practices of the people who lived during that time. Pottery is one of the most informative archaeological materials because its shape often reflects not only how it was manufactured and used, but also the broader historical developments that shaped its production. However, identifying subtle changes in ceramic forms has traditionally relied on visual comparisons, making it difficult to quantitatively trace how pottery evolved over time and what these changes reveal about past societies.

Investigating this, Associate Professor James Frances Loftus from the Institute of Future Science, the Institute for Liberal Arts and the School of Environment and Society, Institute of Science Tokyo (Science Tokyo), Japan, investigated how the shapes of large ceramic vessels known as “Ogame” evolved during Japan's Edo period (1603–1868). Published in the journal Open Archaeology on 19 August, 2026, the study combines Geometric Morphometrics (GMM) (quantitative measurement and analysis of shape) with a Random Forest machine learning model to analyze the shapes of 243 jars recovered from 11 kiln and mortuary sites across the Saga and Fukuoka regions of Japan. The artificial intelligence (AI)-based approach also enabled the researcher to classify jars that lacked secure dates, addressing a longstanding challenge in historical archaeology.

“Even ordinary household pottery can preserve a surprisingly rich record of technological and social change,” explains Loftus. “By combining GMM with machine learning, this study was able to quantify subtle changes in pottery shape that would have been difficult to recognize consistently through visual observation alone.”

Ogame were indispensable containers in early modern Japan, serving a wide range of purposes including storing water and soy sauce, transporting agricultural fertilizers, collecting human waste, and even functioning as burial jars. Supporting both everyday life and burial practices, these versatile vessels played an important role throughout Edo-period society. Although previous studies have shown that the consolidation of Tokugawa domain control, the Qing maritime trade ban, and the expansion of domestic production networks transformed the production and distribution of porcelain, far less attention has been paid to whether these same historical developments also influenced everyday utilitarian ceramics such as Ogame. To measure the differences in their morphology, researcher digitized the outlines of each vessel using Elliptical Fourier Analysis, which is a GMM technique that captures subtle changes in shape. He then trained a Random Forest model to classify undated jars into different chronological stages based on these morphological characteristics.

The results revealed that jars produced during the early 17th century displayed considerable variation in shape, whereas vessels made during the 18th century became increasingly uniform. This transition coincided with major historical developments, including the consolidation of the Tokugawa shogunate, the Qing maritime trade ban, and the expansion of domestic production networks. While archaeologists have long argued that these developments transformed ceramic production, this study provides the first quantitative evidence demonstrating that these broader historical changes were reflected in the evolving forms of everyday pottery. These shifts in patterns suggest that increasing regulation and specialization of ceramic workshops shaped production, while allowing the vessels to be adapted for specific cultural needs.

The researcher also discovered that the shape of vessels reflected differences in function. Jars recovered from the kiln sites generally had broad shoulders, flared rims, and relatively compact lower bodies, making them well suited for storing and transporting liquids and fertilizers. In contrast, the jars which were excavated from burial sites displayed taller, narrower, and more enclosed structures, indicating that they were deliberately designed or selected for funerary purposes rather than simply being reused from domestic settings.

“This study provides the first quantitative evidence that Edo-period Ogame became increasingly standardized over time while also adapting to different functions in response to broader historical developments. Furthermore, it highlights the potential of AI-assisted shape analysis to reveal how subtle changes in pottery morphology reflect wider technological, social, economic, and political change,” says Loftus.

Written historical records often focus on political elites and major events, whereas everyday artifacts such as Ogame offer valuable evidence of the lives of ordinary people. By combining archaeological expertise with AI-assisted analysis, the study demonstrates how material culture can complement historical records to reveal social and economic changes that might otherwise remain hidden.

In the future, Loftus hopes to integrate quantitative shape analysis with other archaeological science techniques, such as portable X-ray fluorescence and compositional analyses, to investigate Edo-period ceramics as well as pottery from different regions and time periods, providing a more quantitative framework for archaeological research worldwide. Integrating GMM with machine learning could help archaeologists reconstruct the manufacturing systems and also study the cultural interactions with greater scientific accuracy—opening new possibilities for understanding past societies through the objects they created.

 

***

Reference
Title: Water, Soy Sauce, Feces, and Death: A Geometric Morphometric and Machine Learning Analysis of Edo-Period Ogame Jars, Japan
Journal: Open Archaeology
DOI: https://doi.org/10.1515/opar-2025-0083

Oases in the desert of Arabia created 'brands' already in the Bronze Age

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Drone photo of the oasis of Qurayyah.

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Credit: Marta Luciani, Qurayyah Joint Archaeological Project CCBY 4.0

Did brands exist before modern society, in non-capitalistic economies? An international team led by Marta Luciani of the University of Vienna has provided unexpected discoveries about trade during the Bronze Age: yes, brands did indeed exist 3,200 years ago. Findings in the oasis of Qurayyah in Northwestern Arabia offer unprecedented insights into the production of a two-color painted pottery. The researchers demonstrated that the vessels were so distinctive, appealing and sought-after that for all purposes they must be considered a 'brand'. The results were recently published in the journal PLOS One. The team included members of M.I.T., the Harvard Museum of the Ancient Near East, OeAI/OeAW, TU Wien and University of Sydney with the support of the Heritage Commission of the Saudi Ministry of Culture.

An international team led by Marta Luciani from the University of Vienna in collaboration with Pamela Fragnoli (OeAI/OeAW) and Johannes H. Sterba (TU Wien) analyzed several dozen Bronze Age pottery vessels from the oasis of Qurayyah in Northwestern Arabia. The researchers were able to dispel old misconceptions about the famous 'Midianite Pottery' and for the first time prove that the pottery's origin was in fact the oasis of Qurayyah. 

"Our discovery sheds light on how even in the arid environment of desert oases, where essential resources such as clay, water and fuel were scarce, local communities already in the Bronze Age were far from marginal but participated in wider networks of technological know-how shared with neighboring regions, such as the Southern Levant and Syria. Oasis-dwellers were resourceful and inventive enough to create their own ceramic repertoire: to cherish at home and eventually export abroad", says study lead Marta Luciani from the Department of Prehistoric and Historical Archaeology of the University of Vienna. 

Criteria for identifying antique brands have been developed

Key to this pioneering research was determining the criteria necessary to identify ancient brands: visual identity, material consistency, technological continuity, centralized production, export circulation, local imitation, intentional commercial scope and cultural reputation.

"Thus our study's implications stretch beyond archaeology and the long-term relationship between humans and natural resources in climatically extreme regions into fields such as the economic mechanisms mediating producer-consumer relationships across time and space", adds Luciani, archaeologist and team leader at the Human Evolution and Archaeological Science (HEAS) network at the University of Vienna. 

"Decisive for this first-time discovery was our interdisciplinary and multi-scalar approach, combining examination of stratified material, vessel-shaping technology, petrographic analysis of ceramic thin sections under the polarizing microscope" explains Pamela Fragnoli, Head of the Ceramic Lab of the Austrian Archaeological Institute at the Austrian Academy of Science (OeAI/OeAW), "cross-checked with chemical fingerprinting of the vessels' composition, down their trace elements obtained via Neutron Activation Analysis" adds Johannes H. Sterba, Head of the Center for Labelling and Isotope Production at the TU Wien.

Doralice Klainscek, PhD candidate at the University of Vienna and study co-author, specifies: "The first set of Qurayyah Painted Ware was produced 3,600 years ago. Our most striking discovery was ascertaining that painted pottery production continued, by constantly evolving (Fig. 2). Four centuries on, ca. 3,200 years ago they manufactured a flourishing repertoire of painted animals and human rituals (Fig. 3): this became the brand that was exported over hundreds of kilometers north to the Southern Levant, to sites like Tell el-Kheleifeh and even the Timna sanctuary of the Egyptian goddess Hathor, and south to North Arabia. But Qurayyah's potting tradition did not stop and continued to be based in the oasis for another thousand years well into the final Iron Age". 

Summary: 

• An interdisciplinary approach to analyze antique vessels found in the oasis of Qurayyah in Northwestern Arabia offers unprecedented insights into brand making and trade in the Bronze age. 
• The researchers concluded that the painted pottery (formerly known as 'Midianite Pottery') was so distinctive, appealing and sought-after that for all purposes it must be considered a 'brand'. 
• Identifying the following criteria: visual identity, material consistency, technological continuity, centralized production, export circulation, local imitation, intentional commercial scope and cultural reputation allowed the scholars to demonstrate how an ancient brand was created. 
• The study's implications stretch beyond archaeology into fields such as the economic mechanisms mediating producer-consumer relationships. 

Bear remains challenge long-held theory on farming’s arrival in Ireland and Great Britain

 

New research led by University College Dublin has rewritten a key chapter in Irish prehistory, revealing that bones long thought to mark the beginning of farming in Ireland belong to bear and wild boar, not cattle.

For more than 30 years, animal remains discovered during excavations at Ferriter's Cove, a small bay on the Dingle Peninsula in County Kerry, and dated to the end of the Mesolithic period (8000-4000 BCE) have been cited as proof that before agriculture became established in Ireland, there was contact between its Mesolithic hunter-gatherers and Europe's Neolithic farming communities.

Believed to be bone fragments belonging to cattle, the find is considered to be the earliest evidence for the presence of domesticated farm animals for the islands of Ireland and Britain.

Now, UCD researchers have shown the famous bones were never cattle at all but belonged to a bear and wild boar.

Detailed in the latest edition of PAST, the newsletter of the Prehistoric Society, the discovery removes one of the most significant pieces of evidence for when agriculture developed in Ireland or Great Britain, and likely forces a rethink of when and how their communities moved from Mesolithic hunter-gatherer lifestyles to Neolithic farming societies.

The new findings are part of a Research Ireland-funded postdoctoral project at the UCD School of Archaeology, led by Dr Martin Moucheron, under the mentorship of Professor Graeme Warren, which is re-examining important Mesolithic archaeological sites using modern scientific techniques.

The new research is part of a Research Ireland-funded postdoctoral project at the UCD School of Archaeology, led by Dr Martin Moucheron, under the mentorship of Professor Graeme Warren, which is re-examining important Mesolithic archaeological sites using modern scientific techniques.

“For at least four millennia hunting and gathering people lived on the island, and there is a common conception that they left little trace and that we know very little about them - unlike the megaliths of Neolithic farmers, who are portrayed in ways that feel very familiar in Ireland,” said Dr Moucheron.

“But there is much we can understand about Mesolithic people just by going back to the sites and material we have, and by looking at them with new eyes and new techniques - and an open mind.”

Ferriter's Cove has occupied a central place in debates about Ireland's prehistoric past since excavations in the 1980s and 1990s uncovered several bone fragments initially identified as domesticated cattle.

The presence of such remains, the so-called "Kerry Cow", contradicted existing theories of the Mesolithic–Neolithic transition in Ireland, and, ever since, have been cited as evidence that its Mesolithic communities had established links with early farmers arriving from Continental Europe.

In collaboration with Dr(s) Benjamin Gearey, Barra Ó Donnabháin, and Margaret McCarthy, from University College Cork, and Kate Kanne (UCD), the original archaeological material from Ferriter’s Cove, which is now stored at UCC, were sent to the CNRS lab in Lille, France, to undergo biomolecular analysis.

Using a technique known as ZooMS that identifies species through proteins preserved in ancient bone collagen, the results found the fragments were not from domesticated cattle as originally thought but instead came from a bear and a wild boar.

As a result, there is currently no archaeological evidence to support the idea that domesticated cattle, and by extension, early farming communities, had reached or influenced Ireland before 4000 BC.

“Ferriter’s Cove is an iconic archaeological site, originally excavated by the Late Professor Peter Woodman, Department of Archaeology, UCC; this new collaboration with colleagues at UCD marks an exciting new phase of research and these remarkable results are set to change our understanding of the earliest evidence for agriculture in Ireland," said Dr Gearey. 

Professor Warren added: “These exciting results show the real value in going back to key sites with new analytical techniques - which can change the stories we tell about our past”

Beyond rewriting one of Ireland's best-known archaeological narratives, the study highlights the value of revisiting important archaeological collections with modern scientific methods, demonstrating how advances can challenge long-held assumptions and reshape the understanding of the past.

Further analyses are now underway to determine whether the bear remains belonged to brown bears or polar bears, with the hope of providing new insights into prehistoric Ireland’s bear populations prior to their extinction during the Bronze Age.

Rethinking how we name and classify our human ancestors following recent evolutionary discoveries

 

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New Monash University research argues our Paranthropus (pictured) and Australopithecus ancestors who lived up to 5 million years ago should be included under the Homo group of species.

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Credit: Ian Towle, Monash University.

Recent advances in our understanding of human evolution challenge the way we currently name and classify our ancestors, according to new research from Monash University.

The research, published in the American Journal of Biological Anthropology, argues that we need a rethink, and proposes reclassifying all species of humans and our closely related fossil relatives that have lived in the past 4-5 million years as part of the Homo genus.

Human evolution is often presented as a straightforward progression through distinct species, from ape-like ancestors, through Australopithecus and earlier members of Homo, culminating in Homo Sapiens that live today.

But the fossil record tells a much more complex story, with new discoveries repeatedly blurring the characteristics once thought to define us and our close relatives.

Lead researcher Dr Ian Towle, a Research Fellow at the Monash Biomedicine Discovery Institute, said recent discoveries are eroding the usefulness and accuracy of current classification, including the current species in our own genus Homo, but also in Australopithecus and Paranthropus, who all lived within the past 5 million years.

“Recent fossil discoveries and advances in evolutionary and genetic analysis make this an ideal time to reconsider whether our traditional taxonomy still accurately reflects human evolution,” Dr Towle said.

“These groups do not necessarily represent distinct evolutionary branches, or ‘clades’, and differences in behaviour and ecology once used to distinguish them have also become increasingly difficult to maintain.

“I propose expanding Homo to include these other groups to provide a more accurate and stable way to represent the complex evolutionary relationships revealed by the growing fossil record.”

In the past 50 years, a growing understanding of evolution has transformed how scientists classify the natural world. 

Modern taxonomy, the science of naming and classifying organisms, increasingly aims to reflect genuine evolutionary relationships, grouping species according to their shared ancestry. 

But when it comes to our own evolutionary history, scientists have been slower to make the transition.

Recent decades have seen a trend to represent a genuine evolutionary group, or clade, of a common ancestor and all of its descendants.

The Homo group have historically been defined by having large brains, sophisticated tool use and particular aspects of anatomy and behaviour. 

But there are now very small-brained members of our genus, and complex behaviours were likely in Paranthropus and Australopithecus.

Dr Towle argues reclassifying Australopithecus and Paranthropus species under the category of Homo will provide a more coherent understanding of our evolutionary history and avoid continual redefinition as we discover new fossils and learn more about our ancestors.

“The more we learn about our ancestors and close fossil relatives, the more we realise how complex and non-linear our family tree is,” Dr Towle said.

“Expanding the Homo genus to also include species of Australopithecus and Paranthropus will allow us to account for differences without regularly reclassifying particular groups.”

Read the research paper: https://doi.org/10.1002/ajpa.70344

A comparison of Neandertal and modern human pelvises

suggests that the male pelvis represents an evolutionary innovation

New study: why do men and women walk differently? A Neandertal pelvis that coexisted with modern humans 35,000 years ago may hold the answer.

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The Neanderthal pelvis

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Credit: Tel Aviv University

A natural mechanism that acts as a shock absorber, stores energy, and releases the energy with every step, potentially facilitating long-distance walking in modern human males.

A new study at the Department of Anatomy and Anthropology of Tel Aviv University, and published in Scientific Reports, offers an explanation for one of the striking differences between men and women: the evolutionary development of the modern human pelvis. By comparing Neandertal pelvises with those of modern humans, the researchers reached a surprising conclusion: the unusual structure of the pelvis may not be that of the Neandertal, as has been assumed for decades, but rather that of the modern human male. According to the researchers, the male pelvis evolved into a unique biomechanical shock absorbing mechanism that stores energy and makes long-distance walking more efficient.

Led by Professor Yoel Rak of the Department of Anatomy and Anthropology at Tel Aviv University, and conducted in collaboration with researchers from Spain, the Technion, Bar-Ilan University, and Ono Academic College, the study is based on a comparison of two nearly complete male Neandertal pelvises, one from Kebara Cave in Israel (Figure 1) and the other from the Sima de los Huesos site in Spain, with dozens of modern human pelvises. Surprisingly, despite their large size and robust construction, the Neandertal pelvises were found to resemble those of modern human females in most measurements and proportions rather than those of modern human males.

For many years, the Neandertal pelvis has been regarded as an anatomically unusual structure requiring a functional explanation of its own. The new findings, however, require a new look at Neandertal pelvises. The ancestral configuration may have been retained in Neandertals and in modern human females, while the modern human male pelvis underwent substantial evolutionary modification, giving rise to a distinctive anatomical configuration.

The central finding of the study is that the hip joints of modern human males are positioned farther forward on the pelvic ring than those of both modern human females and male Neandertals. According to the researchers, this shift created a new mechanical system in which the anterior thigh muscles, attached to the front of the pelvis, function much like a spring, while body weight acts on the posterior part of the pelvis (see Figure 2).

Professor Rak explains that during every step of bipedal walking, the body's center of mass drops downward. This drop traumatizes  the joints and requires energy to raise the body again in preparation for the next step. According to the new model, the distinctive geometry of the male pelvis enables the thigh muscles to cushion the drop of the body's center of mass, store potential energy during the step, and then release that energy immediately afterward-- effectively "springing" the body upward into the next step.

In this way, the pelvis functions as a natural shock-absorber and energy-return system. It may reduce energy expenditure, improve walking efficiency, and thereby provide a significant advantage during long-distance travel on foot. The change in the position of the hip joints also required additional structural adaptations, including the thickening of the pubic bone and deepening of the anterior portion of the pelvis to withstand the new mechanical loads (see Figure 2).

Modern human females, by contrast, could not adopt the full suite of these modifications. According to the researchers, the constraints imposed by childbirth require a relatively shallow pelvis and a sufficiently wide birth canal. As a result, the female pelvis remains closer to the ancestral configuration—the same general configuration found in male Neandertals.

Professor Ella Been of Ono Academic College, a co-author of the study, adds: “This study demonstrates that questions about human evolution are not confined to the distant past. Understanding the evolution of our walking mechanism can contribute to contemporary research in biomechanics, musculoskeletal medicine, rehabilitation, and injury prevention. The perspective provided by the Neandertals helps us better understand the modern human body.”

Professor Rak emphasizes that the findings of the study change the way we understand the evolution of the human pelvis. It is not the Neandertal pelvis that is the anomaly requiring explanation. Rather, it is the pelvis of the modern human male. The mechanism that evolved within the human male represents the evolutionary innovation (Figure 3).

The researchers note that the study presents a new biomechanical model that may explain a substantial part of the human pelvis’s sexual dimorphism—the anatomical differences between females and males. The research also demonstrates that even in human macroscopic anatomy, a field that might appear to have been thoroughly explored, there is still potential to uncover previously unrecognized structures, geometries, and mechanisms of biological significance.

Link to the article:

https://www.nature.com/articles/s41598-026-59915-8

Ancient maritime voyagers carried symbolic art 4,000 years ago

A 4,000-year-old painted stone plaque discovered on a remote Indonesian island is the first known example of portable art belonging to the Austronesian Painting Tradition (APT), providing a rare glimpse into the symbolic world of some of history’s greatest maritime voyagers. 

 

Caption

A 4,000-year-old painted stone plaque discovered on Wetar Island, Indonesia.

Credit

Shimona Kealy/Australian Nattional University.

The discovery was made by an international team led by archaeologists from The Australian National University (ANU) and Indonesia’s National Research and Innovation Agency (BRIN) during excavations at Huknaur rockshelter on Wetar Island, eastern Indonesia. 

The plaque bears a distinctive red concentric-circle and radiating “sun-ray” design characteristic of the APT – a style of rock art found across eastern Indonesia and the Western Pacific in regions where Austronesian languages are spoken. 

Although APT paintings are widespread, most occur on cave and rockshelter walls and are difficult to date, leaving their chronology poorly understood. The Wetar plaque provides the first evidence that these designs were also painted on portable objects, while its securely dated archaeological context provides a rare age for this characteristic motif. 

Lead author Professor Sue O’Connor, from The Australian National University (ANU), said the discovery changes our understanding of how these symbols may have been used. 

"This is the first portable example of Austronesian painted art ever found archaeologically,” Professor O’Connor said. 

“Portable symbols could travel with people and may have helped communicate shared identities, affiliations and beliefs between island communities. Similar sun-like designs were historically painted on boats and other objects, where they could function as symbols of protection and group identity.” 

Co-author Dr Simona Kealy, of the ANU, said radiocarbon dating of the archaeological deposits placed the plaque between approximately 4,090 - 3,900 years ago, when Austronesian-speaking peoples were rapidly dispersing into Island Southeast Asia. 

“This discovery shows that the characteristic sun-ray motif was already part of the APT during the earliest Austronesian expansion into southern Wallacea,” Dr Kealy said. 

 “These people were extraordinary seafarers, rapidly dispersing across thousands of kilometres of ocean. The Wetar plaque shows that art and shared symbolic traditions were part of this great maritime dispersal from its earliest phases.” 

The plaque was found in a preceramic layer, indicating that the APT reached Wetar before pottery – one of the principal material traits traditionally used by archaeologists to trace Austronesian expansion. 

ANU co-author Dr Ceri Shipton said this provides a new perspective on what the earliest Austronesian pioneers brought with them. 

“This discovery shows that Austronesian pioneers arrived with a compelling ideology represented by the APT paintings, prior to more extended contacts bringing pottery,” Dr Shipton said. 

“People didn’t just carry technologies and possessions when they voyaged to new islands. They carried ideas, identities, and new ways of understanding the world.” 

The study, 4,000-year-old painted plaque from Southeast Indonesia reveals Austronesian Painting Tradition preceded Neolithic pottery, will be published in the Proceedings of the National Academy of Sciences (PNAS). 

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2611580123 

Last common ancestor, no matter its feet, could have been a vertical climber

 New research suggests that no matter what we eventually determine the last common ancestor of humans and chimpanzees to be, we’ll learn it was a primate that climbed trees.

Humans and chimpanzees began their separate evolutionary paths between 6 and 7 million years ago when they split from the last common ancestor (LCA) they shared. Debate about the LCA hinges in part on the tree-dwelling environment from which humans emerged – which involved living among the high-up horizontal branches or being able to get there from the ground, or, more likely, both.

Chimpanzees have ankle flexion that makes them skilled tree trunk climbers, but monkeys have been thought to navigate trees with their arms – which would influence what kind of ancestor we’re looking for, one that climbed up trunks or lived in treetops full time.

Video evidence from West Africa suggests there may be no such distinction, at least based on foot structure: Researchers from The Ohio State University observed and confirmed with measurements that wild sooty mangabey monkeys, known to have feet that lack chimps’ versatile ankles, display foot bone flexibility that facilitates vertical climbing up skinny tree trunks to hide, forage or sleep.

“People are making behavioral inferences from fossils, and some say a monkey can’t vertically climb as well as an ape can,” said first study author Luke Fannin, assistant professor of anthropology at Ohio State. “We’re saying there’s a functional equivalence here. So you can’t rule out vertical climbing just because something doesn’t have a chimpanzee-like foot.”

The research appears this week in Proceedings of the National Academy of Sciences.

Identifying the last common ancestor is considered key to helping us understand what led to bipedalism, which is done habitually only by humans. We know we’re apes, but this study makes the point that even if the ancestor had a more monkey-like foot morphology, it could still climb like an ape.

“Part of paleoanthropology is understanding how our evolution happened, and it’s often through the hallmark of how we move because modern humans move quite differently than our cousins, the chimpanzees, do, and they’re the living primate we’re most closely related to,” Fannin said. “And we’re trying to understand why that is.”

Fannin recorded the videos of mangabeys in the wild at the Taï Forest Monkey Project field station in Ivory Coast that is co-directed by W. Scott McGraw, professor and chair of anthropology at Ohio State and senior author of the paper.

“The great thing about having the video is that it allows us to capture exactly what the monkey is doing in a high-resolution manner. So we can actually say how the joint is loaded. Before, we had hunches, but in this way, it’s far more precise,” McGraw said.

The chimpanzee ankle can flex upward at a 45-degree angle during a tree climb, compared to most human ankles’ capacity to flex about 20 degrees. Fannin found that the mangabey foot achieves a 46-degree flex in its midfoot during a vertical climb.

This poses a challenge to differing schools of thought about how the LCA moved and the kind of foot it needed to get around a forest environment – theories differ on whether the foot structure was required to be more like a chimp’s or a monkey’s.

“What’s neat about this paper is it adds clarity, but it also makes the broader picture more fuzzy,” McGraw said. “Because this notion that you have to have a foot like an advanced ape to vertically climb, which is a difficult task, is not true. You’ve got a bunch of monkeys that aren’t extinct – and which can be filmed – that are very competent at performing a biomechanically challenging behavior right now in a forest in West Africa.

“The videos that Luke made in Taï are particularly important because they provide some of the first kinematic documentation of a locomotor behavior in a monkey that has largely been unrecognized or underappreciated.”

There are modern hunter-gatherers and human foragers who are competent vertical climbers as well, a skill believed to be associated with flexibility in their ligaments, tendons and muscles rather than their foot bones.

But Fannin and McGraw note that though modern humans may be defined by walking on two feet, we are focused on ascent, on reaching new heights in a literal sense – a sign that our arboreality, that ancestral connection to trees, is not just anatomical but also a behavioral hallmark.

“Arboreality is fundamental to understanding primates – including ourselves – because it has shaped our body to a large degree: hands and feet, wrists and ankles, nails instead of claws, etc.,” McGraw said.

Added Fannin, “Regardless of where you’re starting from, which we don’t know yet, vertical climbing is universal and the anatomy is going to perform that behavior. So I think that to get at the question of a monkey-like or ape-like last common ancestor, we need more fossils.”