Homo Fabricator

Is Tool Use Monkey Business or Unique to Humans?

If you walk through a home improvement store these days, you might say to yourself, “I wish I had all those tools.” Sophisticated tools make building and repair jobs easier. They also reveal the ingenuity of the toolmakers.

Humans are not the only creatures to manufacture and use tools. Biologists have long observed chimpanzees, orangutans, monkeys, ravens, and crows, among others, making and using wood and/or stone tools. Anthropologists describe similar tool use among Neanderthals, Denisovans, and Homo erectus. What do the quality and kinds of these ancient tools, compared and contrasted with tools today, tell us about the history and nature of humanity vis-à-vis other primate species?

Ancient Tools Found in South America

Over the past quarter century, various research groups have announced that humans settled in South America some 50,000–32,000 years ago.¹ They’ve based their conclusion on the discovery of stone tools at five sites in northeastern Brazil—Pedra Furada, Sitio do Meio, Vale da Pedra Furada, Toca da Tira Peia, and Santa Elina. These ancient dates precede by far those established by other research studies that indicated that human occupation of North and South America began only about 16,500 years ago.² This discrepancy has caused some researchers to speculate that the stone tools discovered in northeastern Brazil must have been manufactured by creatures other than humans. They suggest the toolmakers were capuchins, one of several species of monkey.

Clues to Their Manufacture & Manufacturers

The tools found at the five Brazilian sites are simple stone implements—hammerstones, fragmented flakes, and tabular stone anvils—made of locally occurring quartzite and quartz cobbles.³ The flaking proves exclusively unifacial (flaked on one face only); the stone sources exist no more than 30 meters away from the tools; and the anvil stones weigh roughly four times more than the hammerstones.

In 2017, archaeologist Stuart Fiedel proposed that the artifacts found at these five Brazilian sites were geofacts (rocks shaped by natural forces) rather than tools.⁴ He suggested that the combination of waterfalls, cascades, and gravity produced all the features of the implements discovered. Archaeologist André Prous, in turn, suggested that such natural shaping of the artifacts may have been accelerated or enhanced by monkeys’ throwing stones from the tops of rock shelters and waterfalls.⁵ However, further research by a team led by Fabio Parenti demonstrated that not all the artifacts’ features could be so explained.⁶ At least some of the artifacts required manufacturing.

So who was the manufacturer? Surprisingly, two research teams independently discovered that capuchin monkeys still living in this same region of Brazil are capable of crafting a large number and diversity of stone tools.⁷ Researchers Tiago Falótico and Eduardo Ottoni found that capuchins manufacture and employ both stone and plant-based tools with notably more variety and sophistication than do chimpanzees.⁸ Primatologists now recognize capuchins as the tool-making and tool-using champions among all nonhuman primates.

Does it now appear more reasonable to conclude that capuchin monkeys, not early humans, manufactured the tools found at the Brazilian sites? To settle the matter, an archaeologist and a paleontologist did a detailed comparison between the ancient artifacts found at the Brazilian sites and tools that researchers have actually observed capuchin monkeys making and using.⁹

At each of the Pleistocene sites where the artifacts were found, capuchins currently assemble tools exclusively from immediately available raw materials. The researchers noted that the capuchin monkeys use the tools primarily for stone-on-stone percussion, for cracking open nuts and seeds, and, secondarily, for digging. They observed the monkeys reusing broken hammerstone parts as new hammers. Although some of the ancient broken-off flakes appeared to have been retouched, the two researchers never observed monkeys reprocessing their stone flakes. All the flakes they used, like those at the five Brazilian sites, were unifacial, showing evidence only of unidirectional flaking. In addition, the sources of the stone implements were rarely more than 20 meters away and never more than 30 meters from where they were being made or used.

In addition to providing evidence that all the artifacts discovered could have been made by capuchin monkeys, the two researchers noted a stark contrast between these tools and those made by humans. For example, they found no evidence of hearths, blades, bifacial flakes, bifacially shaped or thinned stone tools, bones with cut marks, exotic raw materials, or any hint of symbolic activity. At early and indisputably human sites, by contrast, the stone flakes recovered are almost entirely bifacial or multifacial.

Researcher Luis Alberto Borrero devoted more than two decades to studying and dating the artifacts from the five Brazilian sites. He found no observable change in the technological characteristics of the artifacts over a time period of ~50,000 years.¹⁰ On the other hand, at all human sites in South America and around the world, dramatic technological advances may be observed on timescales of just a few centuries or less.

Evolutionary Implications

Foundational tenets of both nontheistic and theistic evolutionary models for life’s evolution include the assumptions that (1) chimpanzees are modern humans’ closest living relatives, and that (2) chimpanzees and humans share a relatively recent common ancestor. Thus, these models predict that chimpanzees would prove the most advanced tool manufacturers and users among all existing nonhuman primates. The latest field research on wild capuchin monkeys runs counter to this key evolutionary prediction.

Adjusting the evolutionary models of human origins to make capuchin monkeys modern humans’ closest relatives does not appear a realistic option. Adult capuchin monkeys weigh 1.4–4.0 kilograms (3–9 pounds), while adult chimpanzees weigh in at 32–70 kilograms (70–154 pounds). Capuchin monkeys possess tails as long as their bodies, while chimpanzees have no tails.

A key component of evolutionary models holds that the technological capability of the bipedal primate species that preceded modern humans, particularly Neanderthals and Denisovans, far surpassed that of nonhuman primates living today. However, the latest field studies on chimpanzees and capuchin monkeys show the absence of any significant (and undisputed) differences between their technological capabilities and those demonstrated by Neanderthals and Denisovans.

Chimpanzees, capuchin monkeys, and nonhuman bipedal primates exhibit no measurable technological advance. Clearly, capuchin monkey tool technology has remained stagnant for the past 50,000 years. The tool technology exhibited by Neanderthals existing 350,000 years ago is the same as that for Neanderthals existing 45,000 years ago. Likewise, anthropologists have detected no measurable technological advance among Homo erectus during the 1.6 million years of their existence.

By stark contrast, early humans rapidly developed complex implements such as the bow and arrow, the tomahawk, and the slingshot. They produced a variety of adhesives and glues and began weaving sinews and threads for the assembly of tool parts. Humans carved ivory to make sewing needles that they then used to manufacture sophisticated items of apparel. They not only made tools for enhancing their survival and wellbeing; they also manufactured complex instruments for expressing music and art. They even collected iron meteorites and cold-forged them into stainless steel tools.

Human Exceptionalism & Creation Implications

Clearly, tool manufacture and use by humans exponentially surpasses such capacities seen among all other primates. Humans possess the largest encephalization quotient (brain-to-body mass ratio). Our brains have a much higher density of neurons and are shaped to accommodate a large parietal lobe. Our digital dexterity and hand–eye coordination allow us to engage in complex weaving and assembly of intricate tool parts. Our remarkable energy efficiency in walking, running, and eating sets us free to devote many hours to tool invention, manufacture, and enhancement.¹¹

These advantages explain why, unlike that of earlier primates, human technology did not stagnate but, rather, grew exponentially more complex. In just a few thousand years we humans catapulted from reliance on simple stone tools to driving a motor vehicle on the surface of the Moon. With every passing month, scientific evidence strengthens the case that we humans are intentionally and uniquely created in the image of God. 

Notes

1. N. Guidon and G. Delibrias, “Carbon-14 dates point to man in the Americas 32,000 years ago,” Nature 321 (June 19, 1986): doi:10.1038/321769a0; Paul G. Bahn, “50,000-year-old Americans of Pedra Furada,” Nature 362 (Mar. 11, 1993): doi:10.1038/362114a0; Eric Boëda et al., “The Chiquihuite Cave, a Real Novelty? Observations About the Still-Ignored South American Pre-History,” PaleoAmerica 7, no. 1 (January 2021): doi:10.1080/20555563.2020.1851500; Robin Dunnell and Linda Hurcombe, “Comment on Pedra Furada,” Antiquity 69, no. 264 (September 1995): doi:10.1017/S0003598X0008203X; David J. Meltzer et al., “On a Pleistocene human occupation at Pedra Furada, Brazil,” Antiquity 68, no. 261 (December 1994): doi:10.1017/S0003598X00047414; Denis Vialou et al., “Peopling South America’s centre: The late Pleistocene site of Santa Elina,” Antiquity 91, no. 358 (August 2017): doi:10.15184/aqy.2017.101.
2. Michael R. Waters, “Late Pleistocene exploration and settlement of the Americas by modern humans,” Science 365, no. 6449 (July 12, 2019): doi:10.1126/science.aat5447; Bastien Llamas et al., “Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas,” Science Advances 2, no. 4 (April 1, 2016): doi:10.1126/sciadv.1501385; Todd A. Surovell et al., “Late date of human arrival to North America: Continental scale differences in stratigraphic integrity of Pre-13,000 BP archaeological sites,” PLoS One 17, no. 4 (April 2022): doi:10.1371/journal.pone.0264092.
3. Guidon and Delibrias, ibid., note 1.
4. Stuart J. Fiedel, “Did Monkeys Make the Pre-Clovis Pebble Tools of Northeastern Brazil?”, PaleoAmerica 3, no. 1 (March 2017): doi:10.1080/20555563.2016.1273000.
5. André Prous, “O Povoamento da América Visto do Brasil: Uma Perspectiva Crítica,” Revista da USP: Dossiê Surgi-Mento do Homem na América 0, no. 34 (August 1997): doi:10.11606/issn.2316-9036.v0i34p8-21.
6. Fabio Parenti et al., “Genesis and taphonomy of the archaeological layers of Pedra Furada rock-shelter, Brazil,” Quaternaire 29, no. 3 (September 2018): doi:10.4000/quaternaire.10313.
7. Michael Haslam et al., “Pre-Columbian monkey tools,” Current Biology 26, no. 13 (July 11, 2016): doi:10.1016/j.cub.2016.05.046; Tomos Profitt et al., “Wild monkeys flake stone tools,” Nature 539 (Nov. 3, 2016): doi:10.1038/nature20112.
8. Tiago Falótico and Eduardo B. Ottoni, “Sexual bias in probe tool manufacture and use by wild bearded capuchin monkeys,” Behavioural Processes 108 (October 2014): doi:10.1016/j.beproc.2014.09.036; Tiago Falótico and Eduardo B. Ottoni, “The manifold use of pounding stone tools by wild capuchin monkeys of Serra da Capivara National Park, Brazil,” Behaviour 153, no. 4 (April 21, 2016): doi:10.1163/1568539X-00003357.
9. Agustin M. Agnolin and Federico L. Agnolin, “Holocene capuchin-monkey stone tool deposits shed doubts on the human origin of archeological sites from the Pleistocene of Brazil,” The Holocene (Nov. 15, 2022): doi:10.1177/09596836221131707.
10. Luis Alberto Borrero, “Human and natural agency: Some comments on Pedra Furada,” Antiquity 69, no. 264 (September 1995): doi:10.1017/S0003598X00082028; Luis Alberto Borrero, “Ambiguity and Debates on the Early Peopling of South America,” PaleoAmerica 2, no. 1 (March 2016): doi:10.1080/20555563.2015.1136498.
11. Hugh Ross, “Humans Are Designed to Think While Walking,” Reasons to Believe (Nov. 8, 2021): https://reasons.org/explore/blogs/todays-new-reason-to-believe/humans-are-designed-to-think-while-walking; Hugh Ross, “Humans’ Chewing Advantage Supports Exceptionalism,” Reasons to Believe (Sept. 19, 2022): https://reasons.org/explore/blogs/todays-new-reason-to-believe/humans-chewing-advantage-supports-exceptionalism.