February 3, 2021 | Jerry Bergman

Thumbs Down on Human-Ape Evolution

Our Unique Thumbs:
Another Attempt to Explain the Chasm
between Humans and Chimps Fails

 by Jerry Bergman, PhD

Attempts to prove that humans evolved from apes have constantly failed. After the myth that we are genetically 98 percent identical to our supposedly closest ancestors—the chimpanzees—had been thoroughly debunked, evolutionists have not ceased to continue looking for other similarities. Before we cover this area, it would be instructive to review the amount of confidence among scientists about that 98 percent claim.[1] It was not the view of only one or two scientists; it was science orthodoxy for years. It was practically a consensus among evolutionists, judging by how frequently the claim was made. The alleged similarity has varied between 96% and 99%, but the upshot has been that our genetic similarity, they kept saying, is extremely close. Science Daily said in 2005,

The first comprehensive comparison of the genetic blueprints of humans and chimpanzees shows our closest living relatives share perfect identity with 96 percent of our DNA sequence, an international research consortium reported today.[2]

The lead author of the main study which came to the 98% conclusion was Robert Waterston, M.D., Ph.D., chair of the Department of Genome Sciences of the University of Washington School of Medicine in Seattle.[3] An article in the leading popular science Journal, Scientific American wrote

We now have large regions of the chimpanzee genome fully sequenced and can compare them to human sequences. Most studies indicate that when genomic regions are compared between chimpanzees and humans, they share about 98.5 percent sequence identity…. These early findings suggested that chimps and humans might typically have sequences that diverge from one another by only about 1 percent.[4]

After noting that individual humans differ genetically by about 0.1 percent which results in a significant variation in appearance and other traits between different humans, the report concludes, “chimps differ from humans by about 15-fold more, on the average, than humans do from one another. … Therefore, perhaps we shouldn’t be so surprised that chimps could be 98.5 percent related to humans.”[5] Such was the spirit of the early 2000s.

Now that we know the actual similarity is more like 85 percent (a 15 percent). This difference produces a genetic chasm between humans and chimps resulting in an over 150-fold difference greater than humans differ among themselves! In spite of the chasm between humans and chimps, evolutionists ignore it. They have never apologized for misleading the public. Some continue to state the 98% figure as fact. Meanwhile, they continue to look for evidence that humans evolved from some chimp like ancestor. Today’s example is the thumb.

The Effort to Prove a Chimp Finger Evolved into the Human Thumb

The human thumb is a major example of the many anatomical designs that set us apart from apes. To evolutionists, who take it as a given that humans and chimps have a common ancestor, they simply ignore the genetic chasm in their efforts to find evidence that a chimp thumb evolved into a human thumb. Gizmodo stated the challenge the evolutionary view poses:

Many primates have opposable thumbs, but none are quite like ours. The human thumb, set in opposition to the other fingers, allows for precision grasping, which anthropologists consider a necessary physical attribute for crafting tools.[6]

Their work is certainly cut out for them. Anatomists recognize that “The human thumb is a marvel” of design, “allowing our ancestors to craft stone tools and radically expand their food choices.” The evolutionist proceeds with conviction of evolutionary ancestry into the chasm, looking for bits of fossil evidence. “New research suggests our agile, dexterous thumbs appeared 2 million years ago, in a development that irrevocably changed the course of human history.”[7] In Science Magazine Jan 2021, Michael Price jumped into the chasm, grasping a slight piece of indirect fossil evidence.

[The] human thumb is a nimble wonder, allowing us to make tools, sew clothing, and open pickle jars. But just how and when this unique digit evolved has long been a mystery. Now, a new study modeling muscle in fossilized thumbs suggests about 2 million years ago, our ancient ancestors evolved a uniquely dexterous appendage while our other close relatives remained … all thumbs.[8]

Since evolutionists “know” by faith that humans evolved from chimps, they seek to learn when this thumb evolved, not whether it did. They would like to have thumb evolution coincide with their story of the emergence of stone tool production and other innovations. University of Tübingen paleoanthropologist Katerina Harvati is the lead author of a new study. She pointed out, “most studies looking into the history of hominin dexterity rely on direct comparison between the modern human hand and the hands of early hominins.”[9] Because this approach has not been successful, other approaches are now being attempted. Her research explored the possibility that an earlier, less evolved, hominin hand existed that has comparatively superior thumb dexterity. The assumption, now falsified[10] is

Homo sapiens, emerged around 300,000 years ago, which means we were latecomers to the human show. Other humans (now extinct), such as Homo habilisHomo erectusHomo naledi, and Homo neanderthalensis (otherwise known as Neanderthals) were around much earlier, with the very first humans appearing approximately 2.8 million years ago and possibly even earlier.[11]

The new research[12] was based on the anatomical concept known as “thumb opposition … action of bringing the thumb in contact with the fingers,” This efficiency is “greatly enhanced in humans” compared to other primates like chimpanzees (which also have opposable thumbs) and is a “central component of human-like manual dexterity.” The researchers integrated “virtual muscle modeling with three-dimensional bone shape analysis to investigate biomechanical efficiency for thumb opposition in the fossil human record.”[13]

Harvati and her colleagues wanted to know if this enhanced thumb opposition efficiency could be detected in early hominin fossils as listed above, and if so, which ones. This methodology produces major problems related to the quality and status of the fossil fragments she evaluated.[14]  Assuming that the oldest stone tools in the archaeological record date back to 3 million Darwin years ago, she speculates under Darwine hypnosis that another hominin genus, namely Australopithecus, may also have had human-like thumbs.

Her team’s effort drew on hand bones of modern humans, chimpanzees, and a number of Pleistocene-era hominins, including Homo neanderthalensisHomo naledi, and three species of Australopithecus. The researchers analyzed bone anatomy. Because soft tissue like muscles are not preserved in the fossils, their presence and location were inferred. They focused on one muscle, opponens pollicis, whose location, function, and muscle attachment sites are known to be similar among all the living great apes. The scientists then created virtual models of the hominin hands and calculate the manual dexterity of each species. The results, they concluded

indicate that a fundamental aspect of efficient thumb opposition appeared approximately 2 million years ago, possibly associated with our own genus Homo, and did not characterize Australopithecus, the earliest proposed stone tool maker. This was true also of the late Australopithecus species, Australopithecus sediba, previously found to exhibit human-like thumb proportions. In contrast, later Homo species, including the small-brained Homo naledi, show high levels of thumb opposition dexterity, highlighting the increasing importance of cultural processes and manual dexterity in later human evolution.[15]

One interesting result was that thumb dexterity in Australopithecus was similar to that of living chimpanzees, supporting the conclusion that Australopithecus was not a link between apes and humans but simply an extinct chimp. The controversial fossil of  Australopithecus sediba, “whose hand, and particularly the thumb, has been described as especially human-like,” has prompted “suggestions that it was associated with tool-related behaviors.”


A number of researchers presented several major valid criticisms of the study. For example, Chatham University professor of biology Erin Marie Williams-Hatala, mentioned the “focus on a single muscle attachment site, known as an enthesis, as a major limitation.”[16] Another concern was that the living great apes have thumbs that are relatively small and cannot directly oppose the fingertips as human thumbs can, a fact largely negating the results of the study.[17]

The authors used “aspects of the shape and size of a muscle attachment complex to approximate the shape and functional abilities of the associated small muscle in the hand.” This particular muscle is very important for moving the thumb, but the “idea that muscle morphology—and by extension, muscle and organismal function—can be gleaned from the associated attachment site is an old and very tempting one that continues to be heavily debated”[18]

Essentially, scientists “simply do not understand the relationship between the morphology of muscle attachment sites and the morphology, and certainly not the functional ability of the associated muscle, to confidently say anything about the latter based on the former.”[19] Another study of muscle attachment sites, which was the main methodology of the paper reviewed here, concluded that the attachment site morphological parameters “do not reflect muscle size or activity. In spite of decades of assumption otherwise, there appears to be no direct causal relationship between muscle size or activity and attachment site morphology, and reconstructions of behavior based on these features should be viewed with caution.”[20]

Another problem was the study was only able to focus on a single, “albeit crucial,” muscle of the thumb “due to the fragmentary nature of the fossil record.” Her team “wanted to include as many specimens from as many fossil hominin species as possible,” but this limitation to one muscle restricted conclusions that could be drawn. Last, Aix-Marseille University biomechanics professor Laurent Vigouroux, whose specialty is the mechanics of the human grip, added “more than 10 different muscles that contribute to thumb movement, and it’s possible that weaker opponens pollicis in some species may have been compensated for by some other muscle or muscles.”[21]


Looking at the criticisms by other scientists in the specific field who discounted the practice of extrapolating muscle attachment to thumb function, we conclude that little weight can be put on the conclusions reached by the evolutionists. Consequently, little confidence can be placed in a study that attempted to determine when and how the chimp thumb evolved into the human thumb. The study did not even provide any evidence that the modern human thumb evolved from some primate common chimp and human ancestor. The chasm between chimps and human remains, which would be expected given the genetic chasm documented by the DNA research.

See Christa Charles’s write-up about Harvati’s work in New Scientist as an example of the uncritical repetition of any story that makes evolution appear to have evidence.—Ed.


[1] Marks, Jonathan. 2003. What It Means to Be 98% Chimpanzee: Apes, People, and Their Genes. Berkeley, CA University of California Press.

[2] New Genome Comparison Finds Chimps, Humans Very Similar At DNA Levelhttps://www.sciencedaily.com/releases/2005/09/050901074102.htm

[3] 2005. Initial sequence of the chimpanzee genome and comparison with the human genome. Nature. 437:69-87. P. 73. 70 September 1.

[4] Deininger, Prescott. 2004. What does the fact that we share 95 percent of our genes with the chimpanzee mean? And how was this number derived? https://www.scientificamerican.com/article/what-does-the-fact-that-w/

[5] Deininger, 2004.

[6] Dvorsky, George. 2021. Human Thumbs Got a Major Upgrade 2 Million Years Ago, Sparking a Cultural Revolution, Study Finds. https://gizmodo.com/human-thumbs-got-a-major-upgrade-2-million-years-ago-s-1846150313/ Emphasis added.

[7] Dvorsky, 2021.

[8] Price, Michael. 2021. Your amazing thumb is about 2 million years old. Science. https://www.sciencemag.org/news/2021/01/your-amazing-thumb-about-2-million-years-old. January 21, 2021,

[9] Dvorsky, 2021.

[10] Bergman, Jerry. 2020. Apes as Ancestors: Examining the Claims About Human Evolution. Tulsa, OK: Bartlett Publishing. Co-Authored with Peter Line, PhD and Jeff Tomkins. PhD.

[11] Dvorsky, 2021.

[12]Karakostis, Fotios Alexandros. et al., 2021. Biomechanics of the human thumb and the evolution of dexterity. increased manual dexterity, a vital component of human-like tool use, in thumb bones dated to about 2 million years ago. Current Biology. 31”1-9. https:// doi.org/10.1016/j.cub.2020.12.041.

[13] Karakostis, et al., 2021.

[14] Bergman, Jerry. 2020.

[15] Karakostis, et al., 2021, p. 1.

[16] Dvorsky, 2021.

[17] Dvorsky, 2021

[18] Dvorsky, 2021

[19] Dvorsky, 2021

[20] Zumwalt, Ann.  2006. The effect of endurance exercise on the morphology of muscle attachment sites. Journal of Experimental Biology. 209:444-454. https://jeb.biologists.org/content/209/3/444.

[21] Price, 2021.

Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,500 college libraries in 27 countries. So far over 80,000 copies of the 40 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.

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