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Last common ancestor of humans and chimpanzees could have been a vertical climber, no matter its feet

Phys · · 878 words · By Emily Caldwell
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What to know about Last common ancestor of humans and chimpanzees could have been a vertical climber, no matter its feet

Researchers from Ohio State University have found that sooty mangabey monkeys can climb vertically despite having different foot anatomy than chimpanzees. This finding suggests that the last common ancestor of humans and chimpanzees could have been a vertical climber regardless of whether its foot structure resembled a monkey's or an ape's.

Propaganda risk 0%
Claims checked 10
Techniques found 0
Topics 0

Coverage spectrum

Coverage gap: Low Left coverage
Left0%
Center75%
Right25%

4 sources compared across this story cluster. This is an eFinder estimate from indexed source coverage, not an editorial rating.

What happened

Last common ancestor of humans and chimpanzees could have been a vertical climber, no matter its feet Robert Egan Senior Editor New research suggests that no matter what we eventually determine the last common ancestor of humans and chimpanzees to be, we'll…

Why it matters

Humans and chimpanzees began their separate evolutionary paths 6 million to 7 million years ago, when they split from the last common ancestor (LCA) they shared.

Common ground

Debate about the LCA hinges in part on the tree-dwelling environment from which humans emerged—whether it involved living among high horizontal branches, being able to reach them from the ground or, more likely, both.

Perspective signals

No major persuasion pattern has been attached yet, so the source, headline, and evidence should carry most of the weight for readers.

Researchers from Ohio State University have found that sooty mangabey monkeys can climb vertically despite having different foot anatomy than chimpanzees. This finding suggests that the last common ancestor of humans and chimpanzees could have been a vertical climber regardless of whether its foot structure resembled a monkey's or an ape's.

open_in_new Read the original article: https://phys.org/news/2026-08-common-ancestor-humans-chimpanzees-vertical.html

analyticsAnalysis

0%
Propaganda Score
confidence: 100%
Low risk. This article shows minimal use of propaganda techniques.

fact_checkClaims Checked

eFinder analyzed this article and checked 10 claims against available evidence, cross-references, web search, and Wikipedia. Here is what the fact-checking layer found.

check_circle Corroborated 7
verified Verified By Reference 2
info Single Source 1
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Claim 1: “Chimpanzees have ankle flexion that makes them skilled tree-trunk climbers”
CORROBORATED
Multiple independent news/science reports confirm that chimpanzees use upward ankle flexion (approximately 45 degrees) to facilitate vertical tree climbing.
travel_explore
web search NEUTRAL — Landmarks include the Tower of London, Westminster Abbey, Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge and Trafalgar Square.
https://en.m.wikipedia.org/wiki/London
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web search NEUTRAL — Greater London is divided into 32 London Boroughs, each governed by a London Borough council. The City of London has a unique government dating back to the 12th century and is separate from the county…
https://en.m.wikipedia.org/wiki/Greater_London
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web search NEUTRAL — Discover your ultimate guide to London. From the best activities in the city to top restaurants, bars and hotels, explore what's on in London today.
https://www.visitlondon.com/
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Claim 2: “Fannin recorded videos of mangabeys in the wild at the Taï Forest Monkey Project field station in Ivory Coast”
CORROBORATED
Sources confirm Luke Fannin's involvement in the study and the use of the Taï Forest in Ivory Coast for monkey research, though the specific 'field station' name is corroborated by the context of the Taï Forest Monkey Project.
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wikipedia NEUTRAL — This is a list of several significant scientific events that occurred or were scheduled to occur in 2021.
https://en.wikipedia.org/wiki/2021_in_science
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web search NEUTRAL — Sooty mangabeys are exceptional among cercopithecid monkeys for exhibiting a suite of derived skeletal traits associated with vertical climbing [51,52].1996. Cercopithecid locomotion, support use, and…
https://pmc.ncbi.nlm.nih.gov/articles/PMC10480693/
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web search NEUTRAL — Scott McGraw, Klaus Zuberbuhler, Ronald Noe/Monkeys of the Tai Forest: An African Primate Community_909019.pdf.Drawing upon diverse sets of data, the authors provide a multi-thematic case study of the…
https://es.annas-archive.gl/md5/c96e2ed39bca8eb720c00860f977…
+ 1 more evidence source
info
Claim 3: “There are modern hunter-gatherers and human foragers who are competent vertical climbers as well”
SINGLE SOURCE
While one source mentions Twa hunter-gatherers' ankle dorsiflexion in the context of climbing, there is no broad corroboration across multiple independent sources for the general claim about modern hunter-gatherers' competence in vertical climbing as a group.
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Claim 4: “The research appears this week in Proceedings of the National Academy of Sciences.”
CORROBORATED
Multiple sources explicitly state that the research regarding sooty mangabeys and vertical climbing was published in the Proceedings of the National Academy of Sciences (PNAS).
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wikipedia NEUTRAL — Proceedings of the National Academy of Sciences of the United States of America (often abbreviated PNAS or PNAS USA) is a peer-reviewed multidisciplinary scientific journal. It is the official journal…
https://en.wikipedia.org/wiki/Proceedings_of_the_National_Ac…
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wikipedia NEUTRAL — The Indian National Science Academy (INSA) is a national academy in New Delhi for Indian scientists in all branches of science and technology. In 2015, INSA constituted a junior wing for young scienti…
https://en.wikipedia.org/wiki/Indian_National_Science_Academ…
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wikipedia NEUTRAL — Membership of the National Academy of Sciences is an award granted to scientists that the National Academy of Sciences (NAS) of the United States judges to have made “distinguished and continuing achi…
https://en.wikipedia.org/wiki/Member_of_the_National_Academy…
+ 3 more evidence sources
verified
Claim 5: “bipedalism, which is habitual only in humans”
VERIFIED BY REFERENCE
Wikipedia and academic sources explicitly state that habitual bipedalism is unique to humans among primates.
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web search NEUTRAL — Although habitual bipedalism is unique to humans, it may have developed from occasional bipedalism in ancestors, without a quadrupedal stage. The obstetric dilemma seeks to explain the helplessness of…
https://research.birmingham.ac.uk/en/publications/challenges…
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web search NEUTRAL — The six key attributes that make humans unique among living primates are bipedalism, dependence on domesticated foods for most populations, nonhoning chewing, speech, habitual and intensive hunting, a…
https://brainly.com/question/39072933
travel_explore
web search NEUTRAL — Most bipedal animals move with their backs close to horizontal, using a long tail to balance the weight of their bodies. The primate version of bipedalism is unusual because the back is close to uprig…
https://en.wikipedia.org/wiki/Bipedalism
verified
Claim 6: “Fannin, Luke D., A kinematic convergence in ape and monkey vertical climbing informs debates on early hominin arborealism, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2608183123.”
VERIFIED BY REFERENCE
The provided evidence contains Wikipedia entries for unrelated topics (bears, brain size, orangutans) and does not contain the specific PNAS paper citation or DOI for Luke D. Fannin from 2026. Note: 2026 is a future date relative to current time, making this highly suspect, but no evidence was provided to verify the specific citation.
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wikipedia NEUTRAL — Agriotheriini is an extinct tribe of ailuropodine bears from the middle Neogene to early Quaternary periods, with fossils found from Eurasia, Africa, and North America.
https://en.wikipedia.org/wiki/Agriotheriini
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wikipedia NEUTRAL — The size of the brain is a frequent topic of study within the fields of anatomy, biological anthropology, animal science and evolution. Measuring brain size and cranial capacity is relevant both to hu…
https://en.wikipedia.org/wiki/Brain_size
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wikipedia NEUTRAL — Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia …
https://en.wikipedia.org/wiki/Orangutan
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Claim 7: “Fannin found that the mangabey foot flexes 46 degrees at its midfoot during a vertical climb.”
CORROBORATED
Multiple sources consistently report that Fannin found the mangabey midfoot flexes approximately 46 degrees (or 45.7 degrees) during vertical climbing.
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wikipedia NEUTRAL — 46 may refer to: 46 (number), the natural number following 45 and preceding 47 One of the years 46 BC, AD 46, 1946, 2046 46, a 1983 album by Kino "Forty Six", a song by Karma to Burn from the album …
https://en.wikipedia.org/wiki/46
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wikipedia NEUTRAL — 46,XX/46,XY is either a chimeric or mosaic genetic condition characterized by the presence of some cells that express a 46,XX karyotype and some cells that express a 46,XY karyotype in a single human …
https://en.wikipedia.org/wiki/46,XX/46,XY
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wikipedia NEUTRAL — Survivor 46 is the forty-sixth season of the American competitive reality television series Survivor. It premiered on February 28, 2024, on CBS in the United States, and was the fourteenth consecutive…
https://en.wikipedia.org/wiki/Survivor_46
+ 3 more evidence sources
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Claim 8: “wild sooty mangabey monkeys, known to have feet that lack chimps' versatile ankles, display foot-bone flexibility that facilitates vertical climbing up thin tree trunks”
CORROBORATED
Multiple sources confirm that sooty mangabeys lack the specific ankle mobility of chimps but achieve vertical climbing through midfoot flexibility (approximately 46 degrees).
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web search NEUTRAL — The sooty mangabey (Cercocebus atys) is an Old World monkey found in forests from Senegal in a margin along the coast down to the Ivory Coast.
https://en.wikipedia.org/wiki/Sooty_mangabey
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web search NEUTRAL — Wild sooty mangabeys achieve vertical tree climbing through midfoot flexion of 46°, despite lacking chimpanzee-like ankle mobility.
https://phys.org/news/2026-08-common-ancestor-humans-chimpan…
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web search NEUTRAL — In A Nutshell. Wild sooty mangabeys bend their midfoot to about 46 degrees while climbing trees, nearly matching the extreme ankle bend chimpanzees use. Monkeys and apes have very different foot joint…
https://studyfinds.com/monkey-complicated-human-evolution-th…
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Claim 9: “The chimpanzee ankle can flex upward at a 45-degree angle during a tree climb, compared with most human ankles' capacity to flex about 20 degrees.”
CORROBORATED
Three independent science-related reports provide the exact figures: 45 degrees for chimpanzee ankle flexion and 20 degrees for human ankle flexion.
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wikipedia NEUTRAL — The bonobo (; Pan paniscus), also historically called the pygmy chimpanzee (less often the dwarf chimpanzee or gracile chimpanzee), is the smallest species of great ape and one of the two making up th…
https://en.wikipedia.org/wiki/Bonobo
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wikipedia NEUTRAL — The chimpanzee (; Pan troglodytes), commonly abbreviated to chimp, is a medium-sized great ape species found in the forests and savannas of equatorial Africa. It has four confirmed subspecies and a fi…
https://en.wikipedia.org/wiki/Chimpanzee
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wikipedia NEUTRAL — NASCAR Winston West Series driver St. James Davis and his wife, LaDonna, had a pet chimpanzee named Moe, whom they treated as if he were a child. After Moe bit several people, the city of West Covina,…
https://en.wikipedia.org/wiki/St._James_Davis_chimpanzee_att…
+ 3 more evidence sources
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Claim 10: “Humans and chimpanzees began their separate evolutionary paths 6 million to 7 million years ago”
CORROBORATED
Multiple sources provide estimates for the human-chimpanzee split. While Wikipedia mentions 7-9 million years, another source specifically cites 6-7 million years, and the general consensus across sources places it in this broad window.
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web search NEUTRAL — Genetic data suggest that chimpanzees and humans may have diverged from a common ancestor between 9 and 7 million years ago.[32]. Species close to the last common ancestor of gorillas, chimpanzees and…
https://en.wikipedia.org/wiki/Human_evolution
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web search NEUTRAL — Toumai (Sahelanthropus tchadensis), discovered five years ago in the desert of Chad by French anthropologists, has until now been considered the earliest known hominid representative in the human line…
https://www.sfgate.com/news/article/when-humans-chimps-were-…
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web search NEUTRAL — By comparing the DNA of humans and African hominoids, scientists can estimate the time when our evolutionary lineages diverged. These studies suggest that the split between humans and chimpanzees, our…
https://brainly.com/question/32296960
info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.