A new report published on April 26 in the prestigious science journal Nature has set the archeological abuzz, claiming that 130-000 year-old mastodon bones unearthed near San Diego were smashed and broken by ancient humans to extract their marrow or to make bone tools. Given the current prevailing scientific view that people arrived in the Americas no earlier than 15,000 years ago, the new study has provoked a firestorm of controversy.
The study, entitled “A 130,000-year-old Archaeological site in Southern California, USA,” examined the Cerutti Mastodon site, discovered in 1992 when excavators working on Route 54 in San Diego County uncovered large bone fragments. The California Department of Transportation, following state protocol, then called in paleontologists from the San Diego Natural History Museum, Richard Cerutti and Thomas Deméré, to work on the site. Dr. Deméré believed the site was potentially important, due what he perceived as an unusual concentration of bone flakes and an odd arrangement of the mastodon’s remains. One of the mastodon’s tusks was found in a vertical position and some femur bones were found side by side, suggesting that the skeleton had been deliberately buried. Dr. Deméré applied for and received an emergency grant from National Geographic to support emergency excavations in 1993.
In the report in Nature, Cerutti and Deméré claim they found “in situ hammer stones and stone anvils” alongside “spiral-fractured bone and molar fragments, indicating that breakage occurred while fresh.” The hammer stones and anvils “display use-wear and impact marks” and the stones are “anomalous” to the location where they were found, indicating “that humans with manual dexterity and the experiential knowledge to use hammer stones and anvils processed mastodon limb bones for marrow extraction and/or raw material for tool production.” The bones were so old, far beyond the range of radiocarbon dating, that it required radiometric analysis of the trace elements uranium and thorium. The analysis, conducted by James Paces of the United States Geological Survey, pointed to a “burial date of 130.7 ± 9.4 thousand years ago.”
The authors conclude that “these findings confirm the presence of an unidentified species of Homo” in the Americas, and thus “substantially revises the timing of arrival of Homo into the Americas.” Who these people were, or when or where they came from, the authors do not venture to guess.
The findings and conclusion have led to strong protests from the archeological community. The primary rebuttal is that the bones could have been smashed by other causes. Vance T. Holliday, an archaeologist at the University of Arizona, argues that the authors “don’t demonstrate that they could only be broken by humans.” Southern Methodist University archaeologist David Meltzer similarly says that “you cannot take broken bones and nondescript stones to make the case, not without demonstrating that nature could not have broken those bones and modified those stones.”
Some archeologists, like Gary Haynes of the University of Nevada Reno argued that it could have been the bulldozers, which “weigh seven to fifteen tons or more, and their weight on the sediments would have crushed bones and rocks against each other.” However, if the evidence in the report is correct, that the mastodon was freshly killed when the bones were smashed, it rules out the bulldozers and begs the question, if humans didn’t do it, what did? Dr. Deméré argued that, “It’s kind of hard to envision a carnivore strong enough to break a mastodon leg bone.”
Other archeologists, such as Michael Waters of Texas A&M’s Center for the Study of the First Americans, feel that the stones described in the paper do not unequivocally look like tools. C. Andrew Hemmings, from Florida Atlantic University, says it is not clear what the humans, if they were humans, were doing, given that a mastodon tooth was shattered along with bones. “Everything that’s broken was still there, so it wasn’t mined for tools, and you’re certainly not getting marrow out of the bone of a mastodon tooth,” said Dr. Hemmings, “So what exactly is supposed to have gone on?”
Virtually every prominent American archeologist has been critical of their findings, including notable mavericks such James Adovasio and Tom Dillehay, yet the authors of this new report were fully aware that their findings would be extremely controversial. In their opening statement they clearly state that not only is the age of when humans arrived in the Americas “a contentious subject,” but that an attempt to propose an early alternative view must “meet the following criteria for acceptance: (1) archaeological evidence is found in a clearly defined and undisturbed geologic context; (2) age is determined by reliable radiometric dating; (3) multiple lines of evidence from interdisciplinary studies provide consistent results; and (4) unquestionable artefacts are found in primary context” Report co-author Steven Holen of the Center for American Paleolithic Research believes that “We’ve made a very good case that this is an archaeological site,” adding that, “I think we’re quite prepared for the firestorm that’s coming.”
It remains to be seen if their conclusions hold up, but, unlike the general tendency in the archeological field, which is to avoid controversy and tow the line, the authors of the report seem to relish the upcoming battle. As Dr. Deméré riposted, “Bring it on.”